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A  PRACTICAL  TREATISE 


Dr.  G.  Evans, 
°"   55  West  89th  & 
New  Tori 

Artificial  Crown-  and  Bridge- Work. 


BY 

GEORGE  EYANS, 


Second  Edition,  Revised  and  Enlarged. 


WITH    547    ILLUSTRATIONS. 


PHILADELPHIA: 

THE  S.  S.  WHITE  DENTAL  5IFG.  CO. 
1889. 


ffKUfc 

Ev  / 

|«g«\ 

«4 

Copyright,  1888,  by 

George 

Evans. 

Copyright,  1889,  by 

George 

Evans. 

To  the  Members 

of  the 

First  District  Dental  jSociety  of  the  jState   of  JVew   York, 

this  book  is  respectfully  dedicated 

by 

The  Author, 


PREFACE  TO  THE  SECOND  EDITION. 


In  a  field  of  practice  so  new  as  that  of  which  this  volume 
treats  it  is  natural  that  changes  and  improvements  in  methods  and 
systems  should  be  evolved  with  unceasing  rapidity.  Although 
less  than  a  year  has  elapsed  since  the  publication  of  the  first 
edition,  the  revision  of  the  work  for  the  introduction  of  new 
matter  has  become  necessary  to  properly  fulfill  the  requirements 
of  a  practical  and  comprehensive  treatise. 

Professional  interest  in  the  subject  of  crown-  and  bridge-work 
continues  unabated.  Judging  from  the  space  its  discussion 
occupies  in  the  journals  and  the  proceedings  of  societies,  this 
branch  of  practice  is  gaining  in  favor.  Many  new  ideas  respect- 
ing it  have  reached  the  profession  through  each  of  the  channels 
named.  From  these  and  from  other  available  sources  careful 
selection  of  methods  and  appliances  possessing  merit  has  been 
made  which  by  incorporation  in  this  second  edition  should 
enhance  its  value  to  the  busy  practitioner. 

The  author  entertains  a  grateful  appreciation  of  the  compli- 
mentary acknowledgments  which  have  been  accorded  to  his 
efforts  and  intentions,  and  hopes  for  an  equally  favorable  estimate 
of  his  labors  in  connection  with  this  edition. 

George  Evans. 

New  York,  July,  1889. 


PREFACE  TO  THE  FIRST  EDITION. 


The  aim  of  the  author  in  preparing  this  treatise  is  to  supply 
an  admitted  want  in  dental  literature. 

Much  that  is  new  in  dentistry  and  much  more  that  is,  by 
many  practitioners  at  least,  only  imperfectly  understood,  is 
involved  in  crown-  and  bridge-work.  Properly  practiced  it 
approaches  a  fine  art;  but  misapprehension  of  the  principles 
underlying  it,  lack  of  judgment  in  their  application,  and  im- 
proper practice  have  conspired  to  prevent  its  general  acceptation 
by  the  profession,  and  it  has  in  consequence  been  only  partially 
indorsed  or  even  whollv  condemned  when  a  better  understanding 
would  have  insured  its  hearty  approval.  Still,  its  possibilities 
are  seen  to  be  so  great  that  at  present  no  other  branch  of 
dentistry  more  engages  the  attention  of  practitioners,  and  in  no 
other  is  a  livelier  interest  or  a  greater  desire  for  real  information 
manifested. 

The  subject  is  here  presented  almost  wholly  from  the  practical 
stand-point,  in  the  belief  that  the  utility  and  esthetic  advantages 
of  crown-  and  bridge-work  may  be  thus  more  readily  made 
apparent  to  the  practical  men  in  dentistry.  To  this  end  the 
various  methods  described  an-  classified  in  systems,  and  their 
treatment  is  made  as  concise  as  their  importance  will  permit 
Due  credit  i~  given  where  ilie  methods  and  descriptions  of  others 
are  need. 

Acknowledgment  is  gratefully  rendered  to  Drs.  II.  A.  Parr, 
of  New  York  City,  E.  Parmly  Brown,  of  Mushing,  X.  Y.,  and 
M.  II.  Fletcher,  of  Cincinnati,  for  personal  assistance. 

George  Evans. 

New  York,  August,  1888. 
8 


CONTENTS. 


PAOC 

Introduction 13 

Artificial  Crown-  and  Bridge-Work 17 

PART   I. 

PREPARATORY    TREATMENT   OF   TEETH    AND    ROOTS   FOR   CROWN-WORK. 

CHAPTER  I. 

The  Pulps  of  Teeth — Their  Preservation  or  Devitalization — Pulp 
Capping 22 

CHAPTER  II. 
Devitalization  of  the  Pulp 27 

(^^^4^lc^^TEn  IIL  //,< 

Pulpless  Teeth, -f-THEiR  Treatment  mw  Disinfection. CU^L.f^vkiAk^/Sl 

0 
CHAPTER  IV. 

Chronic  Alveolar  Abscess 35 

CHAPTER  V. 
Shaping  Teeth  and  Roots  for  Crown-Work 39 

PART    II. 

ARTIFICIAL   CROWN  WORK. 
THE    PORCELAIN    SYSTEM. 

CHAPTER  I. 

Porcelain  Crowns 48 

The  Bonwill  Crown..  49 

The  How  Crowns  and  Methods 55 

The  Gates  Crown 62 

The  Foster  Crown 62 

The  Howland  Crown 63 

The  Logan,  Brown,  and  New  Richmond  Crowns 63 

>Remarks  on  the  Use  of  Porcelain  Crowns 72 


10  COXTEXTS. 

CHAPTER  II. 
S/VyJ^S^^  page 

Porcelain  Crown-  wit^/G^lU  Collar  Attachment 74 

CHAPTER  III. 
The  "Weston  Crown 78 

CHAPTER  IV. 
Porcelain  Crowns  with  Rvn«»»«a-  Vulcanite  Attachment 81 


THE    GOLD    SYSTEM. 


CHAPTER  V. 
Porcelain  and  Cold  Crown,  without  a  Collar 82 


CELAIN   AND    GOLD    CROWN,  WITHOU7 


CHAPTER  VI. 

Gold  Collar  Crowns 84 

The  Construction  and  Adaptation  of  Collars 84 

CHAPTER  VII. 

Gold  Collar  Crowns  with  Porcelain  Fronts 89 

Incisors  and  Cuspids 89 

Bicuspids  and  Molars 92 

CHAPTER  VIII. 
All-Gold  Collar  Crowns  for  Bicuspids  and   Molars   constructed 

in  Sections 95 

%.e^Urt^>     a-^L   &UA-kc*l*    _ — , — 

CHAPTER  IX. 

The  Gold  Seamless  Cap  Crown 104 

Incisors,  Cuspids,  and  Bicuspids,  with  Porcelain  Fronts 104 

All-Gold  Bicuspids  and  Molars 106 

CHAPTER  X. 
"•Gold  Seamless  Contour  Crowns 110- 

CHAPTER  XL 
Gold  Crowns  with  Porcelain  Fronts  for  Teeth  with  Living  Pulps  119 
Collar  Crowns  Hvgienically  Considered 122 

CHAPTER  XII. 

%t%{  iai.   PoBHfl  OI  Gold  C'kowns  with   Porcelain  Fronts 124 

The  Parr  Crown 1^4 

The  Leech  Crown 125- 

Low  (,'r  'Wii l*2»i 

The  P<-rry  Crown 128 


CONTENTS.  11 

CHAPTER  XIII. 

PACK 

Drowning  Fractured  Teeth  and  Roots — Crowning  Molar  Roots 
decayed  apart  at  bifurcation — crowning  in  cases  of  irregu- 
LARITY   130 

Longitudinal  Fracture  of  the  Crown  and  Root  130 

Fracture  of  the  Crown  with  Slanting  Fracture  of  the  Root 131 

Crowning  Molar  Roots  decayed  apart  at  the  Bifurcation 132 

Dr.  Farrar's  Cantilever  Crown 132 

Methods  of  Crowning  in  Cases  of  Irregularity 133 

CHAPTER  XIV. 
Partial  Crowns 134 

CHAPTER  XV. 

Finishing  and  Polishing — Process  of  Cementation 142 

Finishing  and  Polishing  Crown-Work 142 

Insertion  and  Cementation 142 

PAET    III. 

BRIDGE-WORK. 

CHAPTER  I. 
Construction  of  Bridge-Work 152 

CHAPTER  II. 
Special  Processes  and  Appliances  in  Bridge-Work 163 

CHAPTER  III. 
Extension  Bridges 170 

CHAPTER  IV. 

IKlUUfcll    BARfBRIDGES C<4L/3~&£ZfCr.M...-* (**» *""* 

EfTT, fi'va  Applications  of  Crown-  and  Bridge-Work 1  -  7 

CHAPTER  Vf. 
Repair  of  Crown-  or  Bridge-Work 185 

CHAPTER  VII. 
The  Hygienic  Condition  of  the  Mouth  as  affected  by  Bridge- Work  187 

CHAPTER  V&T. 

[Detachable  and\PvEMOVable/Bridge-Work 189 

Dr.  Winder's  Sectional  Crown  Method 189 

Dr.  Litch's  Method 192 

Dr.  R.  W.  Starr's  Methods 194 

Dr.  C.  M.  Richmond's  Method 200 

Dr.  Parr's  Methods 200 


12  CONTENTS. 

CHAPTER  ]% 

PAGE 

Removable  Plate  Bridges 206 

Dr.  Waters's  Methods 218 

CHAPTER  if 
The  Low  Bridge 222 

CHAPTER  XTv 
Dr.  Knapp's  Methods 227 

CHAPTER  XlA.1 
Dr.  Melotte's  Method 232 

CHAPTER  XIII. 
Partial  Cap  and  Pin-Bridge  Methods 236 

CHAPTER  Xiyj" 

The  Mandrel  System 245 

Detachable  Bridge-Work 257 

CHAPTER  XV. /A 

Porcelain  Bridge-Work 262 

Dr.  Brown's  Method 262 

CHAPTER  -FHr/y 

Crown-  and  Bridge- Work  combined  with  Operative  Dentistry  in 
Dental  Prosthesis 272 


PART   r-¥/$> 


MATERIALS    AND    PROCESSES    USED    IN    CROWN-    AND    BRIDGE-WORK. 

CHAPTER  I. 
Plate  and  Solders 281 

CHAPTER  II. 

Porcklain  Teeth 285 

CHAPTER  III. 
M'n.iis  and  Dim 286 

CHAPTER  IV. 
SoLSBBDra 288 

CHAPTER  V. 

aUKSVM   and   Arn.i anckn 290 


INTKODUCTIOK 


Of  the  origin  of  the  art  of  dentistry  no  one  can  speak  with  cer- 
tainty, as  its  early  history  is  shrouded  in  the  mists  of  antiquity ; 
but  dental  operations  are  recorded  in  very  remote  times. 

References  are  made  to  the  art  in  the  writings  of  Hippocrates, 
in  the  fifth  century  B.C.  Martial,  the  Latin  poet,  in  the  first 
century  B.C.,  says  that  a  Roman  dentist  "  Cascellius  is  in  the 
habit  of  fastening  as  well  as  extracting  the  teeth."  To  Lelius 
he  says,  "You  are  not  ashamed  to  purchase  teeth  and  hair;" 
and  adds  that  "  the  toothless  mouth  of  Egle  was  repaired  with 
bone  and  ivory ;"  also,  that  "  Galla,  more  refined,  removed  her 
artificial  teeth  during  the  night." 

Horace,  in  the  same  century,  cites  the  case  of  the  "  sorceresses 
Canidia  and  Sagana  running  through  the  city  and  losing  the  one 
her  false  hair,  the  other  her  false  teeth." 

Galen,  the  celebrated  physician,  in  the  second  century  a.d., 
also  speaks  of  the  art  of  dentistry  as  being  then  practiced. 

These  early  operations  were  limited  to  the  extraction  of 
offending  teeth  and  the  replacement  of  those  which  had  been 
lost  with  substitutes  which  were  retained  in  position  by  means 
of  narrow  bands  or  ligatures  attaching  them  to  the  adjoining 
natural  teeth,  and  without  the  use  of  plates.  Crude  as  they 
were,  they  formed  the  first  expression  of  the  art  of  dentistry,  a 
beneficent  art  from  the  beginning,  in  that  it  sought  to  restore 
pathological  or  accidental  defects.  Confined  to  the  simplest 
operations,  it  existed  for  centuries,  and  then  was   apparently 

13 


14  INTRODUCTION. 

lost  during  the  Dark  Ages,  to  reappear  when  the  more  general 
diffusion  of  knowledge  ushered  in  the  modern  era  of  science 
and  invention. 

After  its  revival,  dentistry,  so  much  of  it  as  was  known,  was 
in  a  measure  a  seeret  art,  the  practice  of  which  even  within  the 
memory  of  men  now  living,  and  they  not  the  oldest,  was  in- 
volved in  mystery  :  hut  recent  progress  has  lifted  the  veil,  and 
dentistry,  in  the  treatment  of  the  teeth  on  correct,  scientific, 
rational  principles,  has  developed  an  art  and  a  science  which 
have  given  it  honorable  rank  among  the  professions.  In  its 
two-fold  evolution  it  has  absorbed  from  every  available  source 
whatever  would  broaden  its  science  or  perfect  its  art.  It  calls 
to  its  aid  anatomy,  physiology,  pathology,  chemistry,  thera- 
peutics, metallurgy,  sculpture,  and  mechanics,  with  each  of 
which  it  stands  in  closer  or  more  remote  relation;  and  the 
practitioners  of  dentistry  who  have  become  the  most  eminent 
and  useful  have  been  men  of  broad  attainments  and  great 
versatility  of  talent. 

I  n  t  lit-  hist  >ry  of  all  progress,  movements  apparently  of  a  more 
or  less  reactionary  character  are  recorded.  In  the  useful  arts 
especially  it  is  not  uncommon  to  find  a  return  to  forms  and 
methods  formerly  used  but  long  since  discarded  and  forgotten. 
So  in  dentistry  we  find  methods  of  treatment  and  modes  of 
practice  once  in  vogue  but  long  fallen  into  disuse,  revived 
with  improvements  and  modifications  that  stamp  them  as  prac- 
tically rediscoveries. 

These  movements  are  not  to  be  regarded  as  retrogressive, 
because  the  modifications  which  accompany  the  reintroduction 
of  practical  ideas  and  inventions  stamp  them  as  real  advances, 
ami  indicate  clearly  that  the  cycle  of  knowledge  is  ever  widen- 
ing  with  experience.  This  volume  demonstrates  how  modern 
dentistry  has  utilized  the  principles  of  some  of  the  simplest 
original  operations,  and  by  u  proving  all  things,  holding  fast  that 


IN  TROD  UCTION.  1 5 

which  is  good,"  has  attained  its  present  honorable  position  in 
both  its  scientific  and  artistic  departments. 

The  history  of  dentistry  of  later  years  is,  in  brief,  a  recital  of 
progress  and  improvement.  The  medical  profession  officially 
recognized  it  as  closely  allied  to  medicine  by  inviting  its  rep- 
resentatives to  take  part  in  the  kttw  International  Medical  Con- 
gress on  the  footing  of  professional  equality. 

Such  is  the  position  which  dentistry  has  attained.  Much  of 
the  progress  which  has  made  its  present  elevation  possible  must 
be  credited  to  the  dental  profession  of  the  United  States,  which 
has  been  justly  termed  the  cradle  of  modern  dentistry.  Here 
the  validity  of  the  idea  that  scientific  knowledge  should  form 
the  basis  of  training  for  practice  was  first  demonstrated  by  the 
successful  establishment  of  dental  schools;  here  the  first  journal 
for  the  interchange  among  dentists  of  thought  and  experience 
was  founded ;  here  the  first  association  having  for  its  object  the 
uplifting  and  upholding  of  dentistry  by  the  mutual  helpfulness 
of  its  practitioners  had  its  origin ;  here,  in  a  word,  dentistry 
was  first  divorced  from  mystery,  here  it  first  passed  the  narrow 
confines  of  a  mere  handicraft  and  earned  for  itself  the  ri^ht  to 
be  classed  among  the  learned  and  liberal  professions. 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Modern  artificial  crown-  and  bridge-work  belongs  to  the 
department  of  dentistry  until  recently  termed  "  mechanical,"  but 

the  judgment,  skill,  and  scientific  information  required  place  it 
far  above  ordinary  mechanical  dentistry,  which  has  sunk  to  a  low 
estate  since  the  introduction  of  vulcanite.  To  such  an  extent  has 
vulcanite,  by  reason  of  its  cheapness  and  ease  of  manipulation, 
superseded  other  materials  demanding  greater  knowledge  and 
skill  in  their  manipulation,  as  to  retard  the  higher  development 
of  prosthetic  dentistry,  and  indeed  to  divest  it,  in  the  hands  of 
those  who  depend  upon  vulcanite,  of  the  dignity  which  should 
belonsr  to  dentistrv  as  a  profession. 

But  modern  crown-  and  bridge-work,  properly  understood 
and  properly  performed,  takes  high  rank  in  dental  art.  and 
offers  wide  scope  for  versatility  of  talent  and  inventive  genius. 
The  varied  and  complicated  cases  presenting  for  treatment  fre- 
quently suggest  to  the  expert  novel  contrivances  and  methods  of 
construction  and  application.  Successful  practice  of  crown-  and 
bridge-work  depends  upon  a  thorough  mastery  of  the  under- 
lying principles,  and  expert u ess  in  the  processes  involved,  gov- 
erned by  sound  judgment  and  perfect  candor.  The  interests  of 
the  patient  should  be  paramount  to  every  other  consideration. 
and  after  a  careful  examination  he  should  be  given  an  accurate 
statement  of  the  applicability  of  the  system  to  his  case,  in  re- 
spect to  usefulness,  appearance,  durability,  and  comfort,  as 
compared  with  other  processes  and  appliances  in  use. 

2  17 


18  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

Surgical  and  mechanical  operations  of  the  most  delicate 
nature  are  required.  Nothing,  indeed,  in  dentistry  demands 
finer  manipulation.  A  practical  consideration  of  the  suhject 
will  show  that  a  knowledge  of  anatomy,  pathology,  and  thera- 
peutics, and  as  well  mechanical  and  artistic  skill,  are  necessary 
to  the  correct  treatment  of  cases  and  the  proper  performance  of 
the  operations  indicated.  Among'  the  principal  steps  in  an 
operation  may  he  named,  first,  the  preparatory  treatment  of  the 
natural  roots  and  teeth  for  the  final  process,  involving  the  diag- 
nosis <>f  present  or  probable  lesions  and  the  prescription  of 
whatever  remedial    or  prophylactic  measures   may  he   needful: 

-i nd,  in  crown-work,  the  adaptation  of  the  artificial  crowns  to 

the  cervical  portion  of  the  natural  roots  and  the  contiguous 
membranes,  and  the  restoration  of  the  articulation  and  the  ana- 
tomical contour;  and,  in  bridge-work,  the  selection  of  suitable 
teeth  "f  roots  for  foundation  piers  or  abutments,  and  the  choice 
and  adaptation  in  constructive  practice  of  the  forms  which  will 
insure  the  highest  degree  of  stability  and  best  sustain  the  force 
of  occlusion,  thereby  avoiding  abnormal  positions  and  condi- 
tion--. 

The  practice  of  crown- and  bridge-work  by  dentists  possessing 
tie-  requisite  attainments  andffoverned  by  correel  ethical  princi- 
pies  jr.  i  a  results  \\  men  t^lfcestablisBnts  value,  removTerroueous 
impressions,  and  insurga  wide  professional  and  public  indorse- 
ment of  this  important  branch  of  prosthetic  dentistry.  Its 
extraordinary  facilities  for  preserving  and  replacing  teeth  are 
dually  making  for  it  the  position  in  dental  art  which  it 
merit--. 


PAET   I. 

PREPARATORY  TREATMENT  OF  TEETH  AND  ROOTS  FOR 

CROWN-WORK. 


PREPARATORY  TREATMENT  OF  TEETH  AXJ) 

roots  for  crown-work,    'gjvjv/n  ^yo^n 

<U  H%t\m  Q3a3AH3Q  ION  Jl 

Preparatory  treatment  of  teeth  and   roots  for  crown-work 

includes,  in  addition  to  the  shaping  required  to  fit  them  for  the 
reception  of  the  crowns,  the  bringing  about  of  the  healthiest 
possible  condition  in  the  teeth  and  roots  and  the  adjacent  parts, 
as  the  cure  of  existing  lesions,  the  removal  of  calculus  where 
necessary,  and  the  adoption  of  such  measures  as  shall  prevent 
the  recurrence  of  old  troubles  or  the  inception  of  new. 

Notwithstanding  all  that  advanced  knowledge  of  therapeutical 
agents  and  skill  in  their  use  permit,  there  are  many  teeth  and 
roots  which  cannot  be  rendered  suitable  for  the  successful  appli- 
cation of  crown-  or  bridge-work.  Roots  which  are  permeated 
and  softened  by  decay,  exposed  or  loosened  from  absorption  of 
the  gums  and  alveoli,  or  affected  with  irremediable  disease  of 
the  investing  membranes,  should  be  thus  classed.  Cases  in 
which  abscess  with  necrosis  has  extensively  impaired  the  walls 
of  the  alveoli  are  equally  intractable. 

Experience  shows  that  the  results  in  this  department  of  den- 
tistry depend  largely  upon  diathesis  or  constitutional  tendency 
and  upon  the  attention  given  to  the  preservation  of  the  health 
of  the  mouth  :  and  these  conditions  should  be  carefully  estimated 
in  the  selection  of  a  system  of  treatment  and  the  method  of  its 
application. 


21 


CHAPTER    I. 

THE  PULPS   OF  TEETH— THEIR    PRESERVATION   OR    DEVITALI- 
ZATION—PULP   CAPPING. 

The  preservation  of  the  vitality  of  the  pulps  of  the  teeth  is  a 
matter  of  as  much  importance  in  connection  with  crown-  and 
bridge-work  as  in  any  other  class  of  operations,  though  the 
excision  of  natural  crowns  for  the  purpose  of  utilizing  the  roots 
as  abutments  for  bridge-work  is  extensively  practiced,  and  is 
defended  on  the  theory  that  the  vitality  of  the  dentine  is  main- 
tained by  the  cementum  after  the  extirpation  of  the  pulp.1 

Dr.  C.  F.  W.  Bodecker,  discussing  the  subject  of  the  "  Dis- 
tribution of  Living  Matter  in  Human  Dentine,"  says,- — 

••  1st.  The  dentinal  canaliculi  are  excavations  in  the  basis- 
substance  of  the  dentine,  each  containing  in  its  center  a  fiber  of 
living  matter.  Besides  the  dentinal  canaliculi,  there  exists  an 
extremely  delicate  net-work   within  the   basis-substance  of  the 

1  Dr.  J.  L.  Williams  says,  "The  life  and  vitality  of  the  cementum  remain  in- 
tact and  uninjured,  and  even  the  dentine  may,  and  undoubtedly  does,  retain  a 
certain  amount  of  vitality,  for  something  analogous  to  a  healing  process  takes 
place  at  the  ends  of  the  broken  fibrilLe  next  to  the  pulp-chamber,  and  by  one 
of  those  wonderful  provisional  conditions  which  we  so  often  meet  with  in  the 
economy  of  the  animal  kingdom  nature  reverses  or  changes  the  origin  of  nutri- 
tive supply,  and  the  material  for  maintaining  the  continued  vitality  of  the  den- 
tine comes  through  the  cementum." 

He  further  says,  "  Every  practicing  dentist  has  observed  that  a  tooth  which  is 
removed  from  c<  ntact  with  the  fluids  of  the  mouth  changes  color.  This  change 
in  color  is  largely  the  result  of  the  evaporation  of  the  water  from  the  organic 
portion  of  the  tooth.  Now,  if  the  apical  foramen  of  such  a  tooth  be  clo-id.  and 
the  tooth  be  then  placed  in  water,  or  preferably)  glycerin  and  water,  in  a  Bhort 

time  it  will  regain  neatly  it-  original  color,  and  at  the  same  time  it  will  be  found 

that  it  has  increased  in  weight.  This  means,  of  emir-'',  that  the  entire  booth  has 
bed  from  the  surface  a  certain  quantity  of  the  fluid,  and  this  fluid  baa  pene- 
trated every  part  of  the  solid  structure  of  the  tooth.  Will  any  one  doubt,  with 
in  view,  that  when  the  tooth  is  in  position  in  the  jaw,  and  surrounded 
by  all  the  delicate  adjustment-  furnished  by  nature,  there  may  be  a  circulation 
of  nutrient  fluids  throughout  the  entire  root  after  the  removal  of  the  |  ulp?" 

It  is  difficult  to  understand  bow  a  saturation  can  be  compared  to  an  infiltration 
controlled  by  vital  circulation.— G.  K. 
•  /  >    ••■    (  i .  pagi 

22 


Plate  II. 


\     \ 


"'        *:  *fa^s**£Ak 


lav 


Pj.atl-  III. 


* 


k  • '■ 


mum.  i:v  M.  If.  PLSTCHEB,  M.  !»..  DeHTXST.     Cincinnati,  OHIO. 


THE  PULPS  OF  TEETH.  23 

dentine,  into  which  innumerable  offshoots  <»t*  the  dentinal  fibers 
pass.  Although  we  cannot  truce  the  living  matter  throughout 
the  whole  net-work  in  the  basis-substance,  evidently  owing  to  its 
delicacy,  we  are  justified  in  assuming  that  not  only  the  dentinal 
cahaliculi,  but  the  whole  basis-substance  of  the  dentine  is  also 
pierced  by  a  delicate  net-work  of  living  matter.  The  living- 
matter  of  the  dentine  is  in  direct  union  with  that  of  the  proto- 
plasmic bodies  of  the  pulp,  of  the  cementum,  and  of  the  enamel. 

"2d.  The  cementum,  as  well  as  ordinary  bone,  is  provided 
with  lacunae  and  canaliculi.  The  lacunae  contain  nucleated 
protoplasmic  bodies,  and  the  canaliculi  hold  offshoots  of  the 
living  matter  of  the  protoplasm.  .  The  whole  basis-substance  of 
the  cementum  is  traversed  by  a  delicate  net-work,  which  in  all 
probability  contains  living  matter,  though  this  is  traceable  only 
in  its  thorn-like  projections  from  the  periphery  of  the  proto- 
plasm and  its  larger  offshoots.  The  living  matter  of  the  cenn  ntum 
is  uninterruptedly  connect  d  with  that  of  the  periosteum,  and  continuous 
with  that  of  the  dentine,  either  thr<>>/</h  intervening  protoplasmic  bodies 
in  the  interzonal  layer,  or  directly  witl>  the  dentinal  fibers." 

This  distribution  and  relative  connection  of  living  matter  as 
described  refers  to  an  existing  state  of  perfect  vitality  of  all  the 
parts.  When  the  pulp  loses  its  vitality,  an  entirely  different 
condition  results.  The  tubuli  are  then  deprived  of  vital  circula- 
tion, except  along  the  line  of  the  outer  portion  of  the  dentine, 
where,  in  the  interzonal  layer,  the  fibrillar  anastomose  with  the 
living  matter  of  the  cementum.  The  vitality  supported  by  this 
anastomosis  is  almost  entirely  confined  to  this  part,  the  nutrient 
supply  being  insufficient  to  assume  the  functions  of  the  pulp  and 
maintain  circulation  in  the  main  body  of  the  dentine.  (See 
Plates  I,  IT,  III.)1 

1  Plate  I. — Longitudinal  section  of  the  root  of  a  superior  bicusp'.d,  at  junction 
of  dentine  with  (  omentum.  U,  cementum  ;  D,  dentine;  I,  interzonal  layer  :  L, 
lacunae  of  cementum.     X  l~;->- 

Plate  II. — A  field  taken  from  Plate  I  in  position  marked  A.  L,  lacunae  of 
cementum;  C,  canaliculi  of  dentine  ;   I,  interzonal  layef*.      X  210. 

Plate  III. — A  field  taken  from  Plate  I  in  position  marked  B.  L,  L,  L, 
lacunae  of  cementum;  I,  interzonal  layer;  D,  dentinal  tul>es  and  their  nearest 
approach  to  the  lacuna.'.     X  210. 

A  study  of  these  plates  demonstrates  the  limited  nature  of  the  anastomosis  of 
the  fibers  of  living  matter  of  the  dentine  and  cementum. 


^ 


24  ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 

Chemical  analysis  of  the  dentine  shows  that  the  organic 
matter,  consisting  principally  of  the  fibrillse,  exists  in  the  pro- 
portion of  nearly  28  per  cent,  to  72  per  cent,  of  lime-salts.1 

When  the  pulp  has  been  removed,  the  devitalized  fibrillse 
still  remain,  and  are  capable  of  generating  septic  gases  which 
will  exert  an  influence  in  producing  irritation  of  the  cementum 
and  pericementum,  no  matter  how  thoroughly  the  root-canal 
has  been  filled  and  the  foramen  closed.  An  examination  of  the 
investing  meinhraiies  of  pulpless  teeth  almost  always  shows  the 
existence  of  abnormal  conditions,  by  which  their  firmness  is  to 
some  extent  impaired,  their  susceptibility  to  acute  inflammation 
increased,  and  their  reliability  as  foundations  for  crown-  or 
bridge-work  greatly  lessened  when  compared  with  teeth  which 
have  living  pulps. 

In  crown-work,  facilities  are  afforded  for  the  preservation  of 
pulps  iii  the  posterior  teeth.  Thus,  in  a  case  verging  on  expos- 
ure, only  partial  removal  of  the  decay  is  usually  necessary,  as, 
when  the  operation  is  completed,  the  natural  crown  will  be 
hermetically  inclosed  by  the  artificial  one. 

Extirpation  is  demanded  for  those  pulps  whose  permanent 
preservation  cannot  he  placed  beyond  doubt,  as  failure  involves 
more  serious  consequences  in  crown-  and  bridge-work  than  in 
filling-operations.  The  lesions  of  the  pulp  which  seem  to  re- 
quire its  extirpation,  according  to  the  generally  expressed  opinion 
"ii  the  subject,  are  exposure  with  hypertrophy,, -rupture  of  the 
•  op  >*  no  .-xiid:"!  ■<  of  p'-isma  in  which  puU;itirni- 1*  vwiWe.  con- 
gestion, and  pulpitis  which  does  not  yield  promptly  to  remedial 

tre^enU^^ 

L™«'  o|fcration°of  capping  a  jWjuIi  anqrartaup— yw*  puip 
should  include,  as  a  necessaA'  precaution  against  subsequent 
irritation,  the  thorough  di^mfectiori  of  any  remaining  decom- 

Accordii     •  •  Berz<  litis  and  Brora,  dentine  consist 

bth-cartifage) 27.61 

Fat 40 

Calcium  phosphate  and  fluoride   ........     86.72 

M  iL'ii'-iiim  plm-pliate  .........        1.18 

Calcium  -■  irbonate 



the  p/roportion  of  living   mattei  and  increases  the  pf-rcentage  of 


THE  PULPS  OF  TEETH. 


25 


l<  -Mil  dentine.  AVi  excellent  method  of  securing  disinfection 
is  by  first  thoroughly  washing  the  cavity  several  times  with 
tepid  water  thrown  gently  from  the  large  point  of  a  syringe 
around  the  sides  of  the  cavity;  then,  taking  measures  to  prevent 
the  entrance  of  saliva,  wiping  the  cavity  with  absorbent  cotton 
and  passing  over  its  surface  a  light  current  of  hot  air  from  a 
hot  air  syringe.  The  heat  should  be  sufficient  to  cause  some 
discomfort  to  the  patient,  but  not  enough  to  produce  irritation 
of  the  pulp.  The  dried  cavity  is  then  immediately  saturated 
with  wood  creasote1  previously  warmed2  to  the  normal  tempera- 
ture of  the  body  by  holding  the  pellet  of  cotton  on  which  it  is 
applied  over  the  flame  of  a  lamp  for  a  moment.  The  creasote 
relieves  any  pain  caused  by  the  evaporation  of  moisture,  and 
disinfects  and  sterilizes  any  decomposed  matter  in  proximity  to 
the  pulp.  The  object  of  the  application  of  the  creasote  having 
been  accomplished,  it  slWrfW  then  be  removed  as  cowaplctoiy  as 
possible.  To  this  end  the  cavity  should  first  be  wiped  with 
absorbent  cotton,  and  hot  air  again  introduced  to  evaporate  the 
creasote  sufficiently  to  give  a  dry  appearance  to  the  surface. 
This  second  application  of  hot  air,  owing  to  the  effect  of_  the 
creasote,  will  cause  very  little  or  no  pain.^  The  pttj&is  then 
capped  with  oxyphosphate.  For  this  purpose  the  cement  should 
be  used  soft.  The  proper  quantity  is  the«  applied  to  one  side 
of  the  cavity  and  brought  over  against  the  bottom  in  such-a 
way  as  not  to  inclose  air  between  the  cement  and  the  surface, 
or  cause  the  slightest  pressure  upon  the  pulp.  This  is  an  opera- 
tion requiring  careful  and  delicate  manipulation.  Properly  per- 
formed, it  is  preferable,  in  most  cases,  to  protecting  the  part 
with  a  plate  or  cap,  of  either  a  metallic  or  non-metallic  sub- 
stance, fitted  to  the  bottom  of  the  cavity  to  avoid  pressure  of  the 
cement;  or  to  the  use  of  concave  caps  filled  with  the  cement; 
as.  owing  to  the  adhesive  character  of  oxyphosphate  of  zinc, 
pressure  from  encompassed  air  is  apt  to  occur  frequently  when 
the  cap  is  adjusted  in  position.  ^L ■ 

1  A  refined  pure  wood  creasote,  such  as  is  prepared  for  dental  uses,  is  the  best 
fur  this  purpose.  Carbolic  acid,  alone  or  in  combination  with  oil  of  cloves,  is 
preferably  used  by  some  operators. 

2  Thermal  shock  to  the  pulp  is  as  unwarranted  from  the  application  of  cold 
cT<aote  as  if  produced  in  any  other  manner. 


S 


-^ 


26 


cu<  r 


TIFJCIAL  CJiOflW-  AXD  BRIDGE-WOHK. 


Where  capping  a  pulp  is  necessary,  it  should  be  preliminary  to 
any  other  operation  to  be  performed.^ A  non-vital  condition  of 
jtte  pulp  in  one  root  of  a  tooth  con/rain dicates  any  attempt  to 
preserve  it  in  any  of  the  other  root/,  in  connection  with  crown- 
and  bridge-work.  The  rubber-dan/,  when  its  use  is  practicable, 
will  be  found  a  material  aid  in  diffrVult  pulp-capping  operations. 


C    rt 


4  u 


CHAPTER   II. 

DEVITALIZATION    OF    THE    PULP. 

In  preparation  for  crown-work  two  methods  of  devitalization 
are  practiced:  the  heroic, — instantaneous  devitalization,  or  ex- 
tirpation,— and  gradual  devitalization  !>v  arsenical  treatment. 

Instantaneous  devitalization  m'accomplished  by  first  administer- 
ing to  the  patient  sufficient  nitrous  oxide  to  produce  partial 
anesthesia,  then  with  a  drill  quickly  opening  into  the  pulp- 
chamber,  and  Ulcerating  the  pulp  well  up  the  canal  with  a  probe 
or  smooth  broach.  Instantly  afterward  a  pellet  of  cotton,  satu- 
rated with  carbolic  acid,  is  forced  up  the  canal,  and,  if  possible, 
left  until  the  next  day,  when  the  pulp  will  be  found  in  a  coagu- 
lated mass  that  is  easily  removed  entire. 

Devitalization  of  the  pulp  as  just  described  is  practicable  only 
in  teeth  in  normal  condition.  In  acute  inflammation,  after  lacer- 
ation of  the  pulp,  warm  water  should  be  gently  injected  into  the 
pulp-chamber,  and  sedative  agents  then  applied.  Subsequent 
treatment  should  be  such  as  will  complete  the  devitalization  and 
extirpation  of  the  pulp.  __^--^ 

Excision  of  ike  crown  and  instantaneous  extir-  pIO  i. 

pation  ofthcpulp  ispracticed  by  many  as  follows: 
Two  parallel  grooves  are  cut  opposite  to  each 
other,  through  the  enamel,  deep  into  the  den- 
tine, one  on  the  labial  porti  >n  of  the  tooth  an  ! 
ln\'\he  other  on  the  palatal  wall,  close  to  the  gum. 
with  a  rapidly  revolving  'rubber  and  corundum 
disk  (Fig.  1).  Then  with  excising  forceps, 
the  cuttinoc-edsres  of  which  are  inserted  in  these 
grooves,  the  crown  is  quickly  severed  from  the  root  (Fig.  2). 
The  pulp  either  adheres  to  the  excised  crown,  leaving  the  canal 
empty,  or  remains  in  the  root,  fully  exposed.     In  the  latter  case, 

27 


-> 


ARTIFICIAL  CROWX-  AND  BRIDGE-WORK. 


Fir,.  2. 


Fig    3. 


a  pointed  piece  of  orange  wood,  previously  cut  to  fit  the  canal, 
and  saturated  with  carbolic  acid,  is  quickly  driven  with  a  blow 
into  the  pulp  toward  the  apex  of  the  root  (Fig.  3).  When  the 
wood  is  withdrawn,  the  pulp  usually  adheres  to  it;  if  not,  the 
wood  is  instantly  reinserted,  cut  off  and  drilled  out  with  the 
pulp,  using  Gates-Glidden  drills  in  the  upper  portion  of  the 
canal.  In  this  operation,  it  is  claimed,  only  trifling  pain  is  expe- 
rienced by  the  patient,  as  the  pulp  is  para- 
lyzed by  shock  in  the  excision  of  the  crown, 
or  by  being  forced  upward  toward  the  fora- 
men and  against  the  walls  of  the  canal. 

The  objections  to  this  operation  are,  that 
if  the  pulp  is  not  successfully  extracted  entire 
with  the  wood,  the  canal  be- 
comes filled  with  clotted  blood, 
which  is  difficult  to  remove 
from  the  extreme  end  ;  also  that 
the  root  and  socket  are  jarred 
by  the  forceps  in  excising  the 
crown  ;  but,  expertly  performed, 
it  is  advantageous  in  many 
cases,  though  it  must  be  confined 
to  pulps  in  normal  condition. 
Devitalization  with  Am  nious  Add. — The  methods  of  devitalizing 
previously  described  arc  applicable  principally  to  the  pulps  of 
incisors  and  cuspids.  In  the  posterior  teeth,  which  do  not  so 
well  permit  the  heroic  treatment,  recourse  is  had  to  arsenious 
acid,  notwithstanding  the  numerous  objections  to  its  use.  Two 
theories  as  to  the  mode  of  its  action  in  devitalizing  are  widely 
entertained:  First,  that  by  producing  irritation  of  the  pulp  it 
causes  its  expansion,  which  -tops  circulation  by  strangulation  at 
the  foramen  ;  the  other  is  thrombosis.1 

This  theory  of  thrombosis  account-  for  the  gradual  devitaliza- 
tion of  the  pulp  toward  the  foramen,  and  is  xwx  likely  the  true 
explanation. 

Whatever  the  action  of  arsenic  on  the  pulp  may  be,  it  always 
causes  an  infiltration  of  the  tubuli  of  the  dentine  with  certain 


D     L.  (     [i  Dental  Science,  Questions  and  Answers,"  page  96 


,_<_■"•-- 1 


:<^ 


DEVITALIZATION  OF  THE  PULP. 


2i> 


constituents  of  the  blood,  probably  the  liquor  sanguinis.  The 
residue  of  the  infiltration,  after  the  devitalization  of  the  pulp, 
remains  in  the  tubuli,  and  increases  the  difficulty  of  producing 
an  aseptic  condition  of  the  dentine.  It  is  asserted,,  tinttraascnie 
produces  deviluliiAaliwj  <►!'  tin-  tiUrill&i.as  \\w  it>i-tht:  cc^u^utui 1 1  \ 
tM'*  iv\  flnmfi  tinnrn>  rmii  involves  that  tt?suv,  while  alter  instan- 
taneous extirpation  of  the  pulp  ttfefrtality  «±fcilie  lU^UrM  is  fairAsU/U-d- 
-uxnt*-tirttnt  priiiifT.vi't^HggrliiPCZnrarfatTon.r^ 


Practical  experience  shows  that  usually  instant  devitalization! 

or  extirpation  is  the  most  satisfactory  in  general  and  final  re-v 
suits.     Arsenic,  when   used,  should  be  applied  directly  to  the 
pulp  in  the  smallest  quantity  possible  to  effect  its  devitalization, 
and  securely  sealed  in  the  cavity.  I   The  application   should  be 
kept  in  position  no  longer  than  is  necessary  to  effect  the  devitali- 


zation of  the  pulp.  J*U»<*Ct*- 


LV~K.-<rC    4. 


■ 


/*i^ 


. 


9 


.    / 


^*-£ 


'-  (£> 


\U 


Plate  IV. 


%\ 


=c=. 


PULPLESS    TEETH 


APTEK    III. 

HEIU   TREATM  EXT-A*©'  DISIX  K ECTION . AujLM&U 


Fio   4 


The  treatment  of  pulpless  teeth  or  roots  consists  in  as  thorough 
;i  performance  as  possible  of  the  following  operations: 

1st.   Removal  of  the  contents  of  the  canals. 

2d.  Disinfection  of  the  root-canals  and  the  dentine,  and  the 
establishment  of  permanent  aseptic  conditions  by  mummification 
of  the  contents  of  the  tubuli. 

3d.  Closure  of  the  apical  foramen. 

A  knowledge  of  the  usual  positions  of  the  root-canals  in  the 
different  teeth  is  essential  for  a  generally  successful  performance 
of  these  operations,  which  are  greatly  facilitated,  in  crtown-work, 
by  the  ease  with  which  direct  access  to  the 
root-canals  is  bbtained^TSee  Plate  IV.)1  An 
ning  is  first  made  into  the  center  oi'  the 
pulp-chamber  in  a  line  with  the  root-canals 
sufficient  to  give  free  and  direct  access  to 
them,  and  any  remaining  portion  of  the  pulp 
removed  with  broaches.  The  canals  are  then, 
guided  by  frequent  explorations  with  a  fine 
probe,  carefully  enlarged  with  Gates-Glidden 
drills  (Fig.  4).  At  least  three  sizes — large, 
medium,  and  small — of  drills  each  for  the 
light-angle  and  the  direct  hand-piece  are  required.  Very  little, 
if  any,  pressure  should  be  put  upon'  them  when  in  motion,  as  they 

1  Plate  IV. — Fig*.  1  and  2  represent  the  superior  and  inferior  teeth  in  trans- 
ver  e  section  through  the  l>ase  of  the  pulp-chamher  in  the  crown,  showing  the 
entrance  to  the  root-canals. 

Figs.  3  and  4  represent  the  superior  and  inferior  teeth  in  transverse  section 
through  the  root-canals  as  they  diverge  from  the  pulp-chamber. 

aa,  bh,  cc,  dd.  //'.  dd,  and  er.  Figs.  3  and  4,  show  the  relative  shapes,  whether 
circular,  oval,  or  Battened,  of  the  root-canals  in  the  teeth  they  severally  repre- 
sent. 

31 


* 


LVD  BRIDGE- WORK. 


■ 
32  ARTIFICIAL  CR<>\ 

wil|  move  forward  of  themselves.  Under  pressure  a  false  passage 
in  a  curved  root  is  possible,  or  the  small  drill  might  be  broken 
off  or  forced  through  the  apical  foramen  with  disastrous  conse- 
quences, where  alveolar  abscess  did  not  exist.  Neither  should 
the!  be  forced  into  canals  closed  by  calcification.      A  slight  pain 

?T  Fig.  5. 


is  usiiallv  experienced  when  thej 
fojnied  bv  the  cpmentum  wjiicjij 

'The  probe-like  points  of  these  drills  do 


the  zone  of  sensibility 
composes  the  end  of  the  root] 


not  cut,  but  simply  guide  the  drills  and 
nfine  them  to  the  line  of  the  canal. 
The  occasional  quick  withdrawal  of  the 
drill  from  the  can  ad  during  the  process  of 
drilling  will  aid  removal  of  the  debris. 
The  use  <>f  these  drills  is  condemned 
by  some  for  reasons  attributable  to  their 
careless  or  improper  employment,  but 
tiny-  arc  indorsed;  in  experienced  hand-, 
for  their  adaptability  to  the  work  under 
[deration^ 

been    |>ropcrlv  opened    up  and   it-   e.  .L- 

i     •    •  • 

tents   I'fiiKivci  iged   out  Willi 

i-pid  '  the   pulp  haK 

U  ,mi  long  devitalized,  /.'il  h   peroxide  o 

h\  drontii.  and   tit«--n -dried  with   cotton. 

TLuj  mouth  is  then    pivporly  protected 

lit  of  hot  ;iir ,TnffW!TtUii><l  tntO'tMt.1  p'fflp- 

^x±u*>»*  < I*  i g . -iff.  at  a  temperature  higher, 

a-  it  leaves  the  nozjjle,  than  (a  comfortable  tor  tin-  finger.     This 

heats  any  pari  of  the  crown   remaining,  and  the  lower  portVoi 


A 


of  the  mot.  A  silver  probe,  tapered  as  fine  as  a  broach  al  the 
point,  an«l  connected  with  an  oval-shaped  mass  of  silver  or  copper 
(Fig.  6)  which  has  been  heated  to  a  dull  red  heat,  is  then  intro- 
duced  into  the  root-canal  (Fig.  7).  As  silver  possesses  remark- 
able properties  as  a  thermal  conductor,  the  heat  is  transmitted 
to  the  point  of  the  probe  vevj  rapidly.1  The  probe  being  inserted 
as  tar  as  possible  up  the  canal,  the  patient  is  directed  to  raise  the 
hand  as  a  signal  should  the  heat  cause  pain,  when  the  probe 
must  be  moved  up  and  down,  or  withdrawn  for  a  moment.  This  j 
procedure,  following  the  previous  application  of  hot  air  with 
the  Bynnge,  evaporates  the  moisture  iffrtTygases  from  the  root- 
canals  and  the  open  ends  of  the  tubuli.  The  heat  also  acts  as  a 
germicide,2  and  carbonizes  any  organic  matter  the  instrument 
•  reaehrs. 

friTe  Th  this  heated  and  dried-out  i  ondition  the  dentine  is  satu- 
rated with  an  antiseptic  agent,  which  should  possess  such  proper- 
ties  as  to  make  its  action  efficient  and  its  e fleets  permanent.     A 
present   experience  finds  bichloride  of  mercury — 3-^  solution — ■ 
[or  iodoform  most  suitable  for  the  purpose.'1      When  both  agents 
used,  the  sublimate1  solution  should  be  applied  first,  then  the 
Iodoform,  after  the  canal  has/ been  diied.     Iodoform  is  mdstj 
Conveniently  ar  plied  iii  a  saturated  solution  in  sulphuric  ether. 
2arboli3  acid  i.nd  lik*  agent*  are  being  discarded  for  various 
iasonsj,  among  which  \are  their  inefficiency  and!  their1  eventual 
^sorption  from  the  dentine.  *-^  ^     *    "~~^  ' 

After  .one  or  more  treatments  in  the  manner  described,' the 
inal  is  dried  and  theRU-amen  closed\/  Of  the  many  materials 
used  for  thevfmrpose,  gutta-percha  is  mostapproved.     When 
--wsed-ln. the  form  of  chloro-gutta-percliaj^rgood  method  is  to  dip; 


(i. 


cam 


^  1  As  a  test  of  the  thermal  conductivity  of  sliver,  heat  the  oval  portion  of  this 
instrument  to  a  dull  red  heat,  and  place  the  broach-like  point  of  the  probe  in  a 
little  water  on  the  end  of  a  cork.  The  water  will  l">il  and  evaporate  in  a  few 
seconds.     ^cv-cnut  <h«4$CtnU  >yr*^  /r-> *$%%&£*:  ^  %2&%'z?{<fi~A— 

2  To  accomplish  the  same  pnd^Ua^T-rT'Tlfteji'ster  iii;<w-fi-  -f  platinum, 

thr.mnr|i  which  h'>t  air  :  ,t  tlu.-.  in  liiU.lll'duus  mar  .. 

elective,  and  less  coin  >-ii i.-nt  than  the  method  detailed. 

:J  Iodol  or  the  dental  tincture  of  iodine-can  be  used  in  place  of  iodoform  should 
the  odor  of  the  latter  render  it  objectionable.  A  small  quantity  of  oil  of  winter- 
green  added  to  the  solution  of  iodoform  aids  in  disguising  the  odor. 


" 


l/i. 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


a  few  shrefls  of  iodoformized  cotton1  in  the  solution,  press  out 
the  surplus,  and  gently  pack  (not  push)  them  lengthwise  into  the 
extremity  of  the  canal.  Cotton  so  prepared  is  incorruptible,  and 
when  properly  inserted  it  effectually  closes  the  foramen,  obviates 
any  danger  of  air  or  the  solution  of  gutta-percha  being  pressed 
through,  and  is  easily  removed  should  anv  subsequent  condition 
require  i t ^Tlie  cari iiL i *  then  filled  with  gutta-percha  or  any 
lef71  material,  prejejre(fcs  Another  method  is  to  prepare  an 
orange  or  h iekoT^wooa^foTnt  to  fit  the  canal,  immerse  it  in  the 


solution  of  gutta-percha,  and  then  press  it  to  position  in  the^ 
canal.    -Ordinary  gutta-percha  should  be  used  to  close  a  foramei 
when  an  abscess  has  just  been  treated  by  injecting  through  it^ 

Successful  treatment  of  pulpless  teeth  depends  not  on  "  imi 

diate  root-filling  after  . extirpation  of  the  pulp,"  but  upon  imme- 

tdiate  root-filling  after  "proittking  ><  thorough  aseptic  condition  of  jhe^ 


canals  and  dentine. 

Ample  room  should  be  left  in  any  root-canal  which  is  t 
receive  the  post  of  a  crown,  as  any  part  of  the  canal  not  occu- 
pied by  the  post  will  be  filled  by  the  retaining  material. 

A  pulpless  tooth  presented  for  crowning,  the  roots  of  which 
have  been  treated  and  filled  in  some  previous  operation,  should 
be  carefully  examined,  and  if  any  doubt  is  entertained  as  to  its 
hygienic  condition  it  should  receive  the  antiseptic  treatment 
above  described,  as  the  ultimate  success  of  crown-work  depends 
largely  upon  the  thoroughness  of  these  preliminary  operations. 

'Cotton  or  wood  points  may  be  iodoformized  by  immersing  them  for  a  sbort 
time  in  a  saturated  solution  of  iodoform  in  ether,  and  then  exp>  sing  them  for  a 
little  while  to  evaporate  the  ether.  The  prepared  points  should  be  kept  in  a  tightly  - 
corked  bottle.  When  this  plan  ie  followed  the  odor  of  iodoform  is  almost  imper- 
ceptible in  the  operating-room. 


/ 


I 


7 


jfc^&W. 


i 


CHAPTER  IV. 

CHRONIC   ALVEOLAR  ABSCESS. 

Many  reeth  and  roots  presented  for  crown-work  are  affected 
with  chronic  alveolar  abscess.  A  general  description  of  an 
effective  method  of  treatment  is  therefore  properly  associated 
with  a  discussion  of  the  subject. 

The  cause  of  chronic  alveolar  abscess  will  be  found  in  a  con- 
tinuation of  those  conditions  which  originally  produced  the  acute 
form.  The  tooth  or  root  being  pulpless,  septic  gases,  generated 
bv  the  decomposition  of  organic  matter  in  the  root-canal  and  in 
the  tubuli  of  the  dentine,  find  an  outlet  through  the  open  foramen 
into  the  apical  space,  causing  pericementitis  and  formation  of 
pus.  The  general  treatment  consists  in  the  removal  of  all  septic 
matter  and  gases  from  the  root-canal  and  dentinal  tubuli,  the 
destruction  of  the  pus-sac,  the  application  of  suitable  therapeutic 
agents,  and  the  adoption  of  measures  to  prevent  further  formation 
of  pus. 

Chronic  alveolar  abscess  is  usually  found  in  the  following 
forms:  1st.  Abscess  with  a  fistulous  opening  in  the  gum,  and 
accessible  through  the  root-canal  and  foramen  of  the  root.  2d. 
Abscess  with  fistulous  opening  but  not  accessible  through  the 
apical  foramen.  3d.  Abscess  from  which  pus  discharges  through 
the  apical  foramen  and  root-canal  with  no  opening  through  the 
gum. 

In  the  treatment  of  abscess  of  the  rirst  form,  the  canal  should 
be  enlarged  as  described  in  the  treatment  of  pulpless  teeth,  and 
the  foramen  opened,  if  possible,  with  a  smooth  broach  without 
the  use  of  a  drill.  Tepid  water  is  then  forced  through  the 
foramen  with  a  fine-pointed  syringe  (Fig.  8)  introduced  well  up 
the  canal,  and  packed  in  with  gutta-percha,  or  pumped  up  with 
cotton  on  a  broach   until  it  passes  into    the   abscess  and  out 

35 


36 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


through  the  fistula.  Peroxide  of  hydrogen  is  next  used  in  the 
same  manner,  until  it  ceases  to  foam  as  it  passes  from  the  abscess. 
Aromatic  sulphuric  acid,  either  pure-or  diluted,  is  then  applied 
'^  •■  rpimiii  idii  mwfrfwn  i  i  fill   i  ImimmiiI 

In  abscesses  of  the  second  form,  where  it  is  impracticable  to 
treat  through  the  foramen,  the  canal  sbould  be  thoroughly  disin- 
fected, and  a  direct  opening  into  the  abscess  effected  by  the  track 
<>f  the  fistula,  enlarging  it  if  necessary.  The  abscess  should 
then  be  thoroughly  injected  with  peroxide  of  hydrogen  and 
afterwards  with  aromatic  sulphuric  acid,  by  introducing  the  fine 
point  of  a  syringe  into  its  deepest  parts.  The  fistula  must  be 
Fig.  8.  kept  open  by  inserting  in  it,  at  each 

injection,  a  strand  of  twisted  cotton 
saturated  with  oil  of  cloves,  the  pa- 
tient being  directed  to  remove  it  in 
a  few  hours,  or  the  next  day,  for 
which  purpose  the  end  should  be 
left  protruding.  When  the  apical 
foramen  is  open,  one  injection  is  usu- 
ally sufficient  to  cure  an  abscess;  but 
when  the  foramen  is  closed  and  the 
abscess  is  treated  through  the  gum, 
several  injections  are  sometimes  ne- 
cessary. 

In  case  of  "  blind  abscess,"  the 
third  form,  first  clean  and  disinfect 
the  root-canal,  then  at  intervals  inject 
the  abscess  through  the  foramen  with  peroxide  of  hydrogen 
until  the  formation  of  pus  ceases,  placing  cotton  saturated  with 
<>il  of  cloves  loosely  in  the  canal  to  exclude  foreign  suhstances. 
Should  this  treatment  fail,  an  opening  through  the  gum  into  the 
abscess  must  he  obtained  either  with  a  lance  and  drill,  or  a  tre- 
phine, and  the  same  course  pursued  as  in  the  firsl  form  ofabscess. 
An  entrance  into  the  apical  space  can  be  made  almost  pain- 
lessly in  the  following  manner,  as  described  by  Dr.  <i.  V.  Black:1 
"  The  mil.  ous  membrane  i-  firsl  dried  at  the  point  at  which  it  is 
desired  to  make  the  opening,  and  napkins  are  so  placed  as  to 

1  American  System  of  Dentistry,  vol.  i,  page  928. 


CHRONIC  ALVEOLAR  ABSCESS.  :;; 

keep  ir  dry.  Then  a  plugging-instrument  with  fairly  sharp 
serrations  and  of  convenient  shape  is  selected.  The  point  of 
this  is  dipped  into  a  95-per-cent.  solution  o\'  carbolic  acid,  and  a 
drop  conveyed  to  the  mucous  membfftne;  this  will  at  once  pro- 
duce a  white  eschar.  Then  a  slight  scratching  motion  with  the 
serrated  point  is  begun,  with  the  view  of  removing  the  t i>-u< ■ 
that  is  whitened.  This  is  continued  until  the  carbolic  arid  is 
thick  with  the  debris  of  the  tissue  torn  up,  then  it  is  dried  out 
and  another  drop  added,  as  before,  and  the  process  continued. 
This  is  repeated  as  often  as  may  be  necessary,  going  deeper  and 
deeper  into  the  tissue  in  the  desired  direction  until  the  hone  is 
laid  bare.  Then  a  fresh  drop  of  the  acid  is  placed  on  the  hone 
and  the  periosteum  carefully  raised  over  a  sufficient  space;  then 
with  a  sharp  chisel  cut  through  to  the  peridental  memhrane. 
This  will  generally  cause  some  pain  and  some  bleeding,  hut 
after  giving  a  little  time  tor  this  to  cease,  and  adding  more  of 
the  acid,  the  apical  space  can  usually  be  reached  without  diffi- 
culty. Xo  blood  should  he  drawn  at  any  time  during  the  opera- 
tion, except  in  penetrating  the  wall  of  the  alveolus.  In  doing 
this  no  tissue  is  removed  until  it  is  anesthetized  by  the  carbolic 
acid.  This  is  a  little  tedious,  but  it  is  almost  painless,  and  the 
general  effect  is  usually  better  than  by  other  modes  of  pene- 
trating the  apical  space.  The  carbolic  acid  has  the  effect  of 
modifying  the  pain,  and  the  opening  left  does  not  close  so 
readily."1" 

After  the  abscess  has  been  cured,  the  root-canals  are  treated 
s**4  tilled  as  described  on  page  31. 


"fli  place  of  aromatic  sulphuric  acid,  if  preferred  or  should  the 

cnsf^TTTTm^tfalL  pjfhpr  .-ni-Lnli,-  acid,  the  sublimate  solution  (  nj^j-jj). 

or  any  other  suitable  t  he'rfrpi.'  uUcai^en  t  cai^kf^use^tn^  most  of 
them  will  be  found  less  prompt  and  less  elective,  especially  if  a 
-lightly  necrosed  state  of  the  wall  of  the  alveolus  ex.intM.V 

Amputation  of -the  Apex  of  a  Root. — In  long-neglected  alveolar 
abscess,  the  pus-cavity  occasionally  involves  the  alveolus  in  such 

1  For  an  extensive  consideration  of  this  subject  the  reader  i?  referred  to  Dr.  J. 
N.  Farrar's  article-  on  "Sulphuric  Acid  o.  Creasote  in  Treatment  <'t'  Alveolar 
Abscess,"  commencing  Dental  Cosmos,  vol.  x\.  No.  7,  and  Dr.  G.  V  Black's 
article  in  the  "  American  System  of  Dentistry,"  vol.  i,  page  929. 


:> 


ARTIFICIAL  CROWN-  ASD  BRIDGE-WORK. 


Flo.  9. 


a  way  as  to  destroy  a  considerable  portion  of  the  pericementum 
of  the  end  of  the  root.  The  ceraentnni  of  that  part  is  conse- 
quently devitalized,  and  the  portion  of  the  root  affected  becomes 
degenerated  in  structure,  and  saturated  with  septic  matter.  In 
this  condition  it  acquires  the  character  of  a  foreign  substance, 
[•roves  a  constant  source  of  irritation,  and  defies  all  efforts  of  the 
membranes  to  perfectly  inclose  or  encyst  it. 

In  such  cases  amputation  of  the  portion  of  the 

root   which   is   denuded   of  pericementum  is  the 

I  best  course  to  pursue.     An  opening  is  made  in 

^^^  the  soft  tissues  above   the  affected  part  wHlt-thc 

Ja***e*!aH=tBBpl*M*<»jand  gradually  enlarged  with  a 

tent  of  lint  or  cotton  until  the  diseased  territory 

is  fully  exposed  (Fig.  9),  when  the  devitalized  end 

of  the  root  and  any  necrosed  bone  in  the  territory 

are  removed  with   a  fissure-drill,  and  the   end  of 

the  root  smoothed.     The  root-canal  is  then  closed 

with  gutta-percha  passed  through  from  within,  the 

surplus  being  trimmed  off  on  the  outsideyf  Cocaine 

can  be  used  in  this  operation. 

Tii'-  orifice  of  the  cavity  in  the  gum  should  be  kept  open  until 

the  cavity  is  filled  by  granulation.     When  the  healing  process  is 

completed,  crown-work  can  be  proceeded  with. 

The  amputation  of  roots  requires  skill  and  experience,  and 
had  better  be  confined  to  the  incisors. 


CHAPTER   V. 


SHAPING  TEETH    AND   KOOTS   FOR   CBOWN-"W 

The  principles  governing  the  process  of  shaping/a  natural 
crown  or  root  for  any  style  of  artificial  crown  with  a  collar 
attachment  require  that  the  cervical  portion  of  the  natural  crown 
and  root  shall  he  given  a  form  that  has  longitudinally-parallel 
sides  gauged  to  the  line  of  the  periphery  of  that  part,  and  that 
any  of  the  coronal  sedtion  present  below  it  shall  be  reduced  at 
least  sufficiently  in  size  to  come  within  this  line.  Such  a  form 
is  necessary  to  admit  o'f  a  perfect  adaptation  of  the  collar. 

The  coronal  section  of  a  natural  crown  to  he  prepared  is 
usually  first  ground  on  the  occluding  surface  with  as  large  a 
corundum-wheel  as  the  case  will  conveniently  admit  (Fig.  10). 


Molars  and  bicuspids  for  all-gold  crowns  should  have  enough 
substance  removed  to  make  a  small  space  between  them  and 
the  antagonizing  teeth,  i  The  approximal  surfaces  are  removed 
straight  from  the  cervical  border  to  the  occluding  surface,  using 
diamond  or  rubber  and  corundum  disks.  (Fig.  11)  and  files,  and 
last  of  all,  as  injury  to  the  approximal  teeth  is  then  more  easily 
avoided,  the  labial  and  palatal  portions,  for  which  small  corun- 
dum points  (Fig.  12)  and  wheels  are  best  adapted.  The  corners 
are  then  rounded.  The  cervical  portion,  which  includes  the 
junction  of  the  dentineaud  enamel,  is  trimmed  so  that  the 
sides. as  illustrated  at  A,  Fig.  13,  are  level  and  parallel  with  the 


39 


40 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


line  of  the  root,  and  as  deep  as  the  collar  is  to  be  placed  (Fig.  14). 
For  this  purpose,  small  corundum  points,  trimmers,  and  files  can 
be  used.     Fig.  15  illustrates  a  drill,  which  in  the  ordinary  hand- 

Fig.  12. 


Fig.  11 


4vv  4-/U^^^^ai\[^ft^ 
piece  or  in  the  right-anglb  attachment  will  easily  and  cpiickly 
aecomplish  this.  Fig.  16  illustrates  another  tfpw*/\vhich  can  be 
in  a  hand-soeket,  bracing  the  hand  by  resting  the  thumb 
on  the  adjoining  teeth.  The  points  should  be  tempered  very 
hard.  Files  shaped  as  shown  in  Fig.  17  are  useful  in  rounding 
angular  portions.     A  smooth,  level  surface  should  be  given  the 


Fig.  13. 


Fig.  14.  Fio.  15.  Fig.  16.     Fio.  V 


Fig.  18. 


* 


cervix.  On  approximal  sides  and  the  curves  to  the  other  sides, 
medium  coarse  corundum  tape  and  wheels  can  be  used  for  this 
purpose. 

A  root-trimmer  or  reducer  recently  devised  by  Dr.  W.  S.  How 
can  be  used  in  combination  with  or  in  place  of  the  appliances 
before  described.  It  is  sel  in  a  cone-sockel  handle.  The  pin  of 
the  center  shaft  is  inserted  in  the  opening  in  the  end  of  the  root 


SHAPISG  TEETH  AXD  ROOTS  FOR  CROWS-WORK. 


41 


and  the  Scraper  point  rotated  around  the  periphery  underneath 
the  gum  margin  (Fig.  18).  The  inward  spring  of  the  flat  scraper 
shank  causes  the  point  to  bear  hard  against  the  root,  while 
following  its  outline  closely.  The  root  end  is  reduced  without 
change  of  contour,  while  its  taper  is  reversed,  so  that  the  greatest 
diameter  is  found  at  the  portion  acted  on  by  the  extreme  end 
of  the  scraper  point  (A,  Fig.  18).  The  milled  nuts  permit  the 
scraper  to  he  adjusted  to  different  sized  roots. 

In  pulplesa  teeth,  the  use  of  excising  forceps  should  be  avoided 
unless  the  parts  admit  of  it  without  serious  shock  to  the  root. 
The  best  plan  is  to  make  a  succession  of  holes  across  the  portion 
to  be  removed  with  a  spear-shaped  drill,  and  then  cut  between 
the  holes  with  a  fissure-bur  or  corundum  disk,  which  will  permit 
of  easy  removal  of  the  part  (Fig.  19). 


Fig.  19.      Fio.  20.       Fio.  21. 


Fig.  22. 


Fig.  23. 


Fig.  24. 


In  preparing  incisors  and  cuspids  for  gold  collar  crowns  with 
porcelain  fronts,  where  the  pulp  is  to  be  preserved,  the  labial 
surface  and  incisive  edge  /hofild  be  ground  down  as  much  as 
possible  without  exposing  the,plflp  or  subjecting  it  to  irritation ; 
the  palatal  portion  at  an  ^ngle  from  the  cervical  borde^fto'the 
incisive  edge,  enough  to  level  its  prominences  of  contour  and 
form  a  slight  space  between  it  and  the  antagonizing  teeth  (Fig.  20). 

""pulpier    inci*nr>;    nrwl    r-n^pwla    alwinlfl    hr>    frrnnnrl    tn    *li  n    inn  p« \ ,) 

tlie  gm-ii  v\t  flip  i-ii.;-ii  pru.tirni ■,  niifj  lilirhll  i   1 1 1 1 1ff*^TffarrrTF*nT 
n  the  pirtH'i'r  h:ilf  (Fii ,    nVj      Bicuspids  which  are  to  have 
porcelain  fronts  are  given  the  same  general  form  (Fig.  22). 

Bicuspids  and  molars  with  or  without  pulps,  for  all-gold  crowns, 
should  have  as  much  of  the   natural  crown  left  as  possible,  as  it 


42 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


offers  a  form  of  attachment  for  the  artificial  crown  which  is 
more  secure  and  more  convenient  than  is  attained  by  any  other 
method  (Figs.  23  and  24).  S^  fm 

For  the  porcelain  system,  incisor,  cuspid,  and  posterior  roots 
are  usually  ground  level  with  the  margin  of  the  gum.  The  palatal 
portion  is  favored  in  some  eases  by  leaving  it  a  trifle  above  the 
margin.  The  root-canal  is  shaped  to  the  form  of  the  post  orpin 
80  that  it  shall  fit  it  tightly.  (For  details  see  the  articles  on  the 
Bonwill  and  Logan  crowns.)  The  occluding  edges  or  surfaces  of 
antagonizing  teeth  should  be  removed  sufficiently  to  allow  ample 
space  for  the  artificial  crowns  or  to  favor  them  in  the  act  of  occlu- 
>i<  >uTj  Corundum  or  composition  wheels  or  points  should  be  kept 
wet  and  cool  in  these  and  other  operations  in  the  mouth 7)/ 

Special  Preparation  of  Badly  Decayed  Teeth  or  Roots. — The  tem- 
porary exposure.of  the  end  of  a  root  or  of  the  cervical  portion  of 
a  brown  for  the  purpose  of  facilitating  or  simplifying  a  crowning 
L  ]  operation,  especially  in  the  adaptation  of  a  collar  or  band,  is 
effected  by  inserting  in  the  pulp-chamber  or  the  root-canal  a 
piece  of  gutta-percha  large  enough  to  admit  of  a  portion  being 
brought  over  against  the  investing  membranes,  to  compress  them 
for  a  day  or  more.  Where  a  secure  attachment  for  the  gutta- 
percha cannot  be  obtained,  a  plug  of  wood  should  be  inserted 
temporarily  in  the  root,  and  the  gutta-percha  held  in  position  by 
being  packed  around  it.  The  root  can  thus  be  exposed  to  the 
border  of  the  alveolar  process  if  desired.  In  bicuspids  and 
mo  ars,  when  decay  extends  up  on  the  cervix  farther  than  will 
the  edge  of  the  artificial  crown  or  the  collar,  the 

Pin      ■'-.  &  ' 

gums  should  be  pressed  up  with  gutta-percha,  the 
decay  removed,  retaining-pits  for  a  filling  made, 
and  the  cavity  filled  with  amalgam  shaped  to  the 
contour  of  the  tooth  (Fig.  25).  In  incisors  and 
cuspids,  when  extensive'  decay  has  destroyed  a 
portion  of  the  side  of  the  root,  a  tight-fitting  tube 
made  of  a  metal  to  which  amalgam  will  readily 
adhere,  and  of  such  size  as  will  admit  the  pin  of  the  crown,  can 
!>'•  inserted  up  the  root-canal  and  the  upper  end  cemented  in 


he 

with   oxypho-phate   and    the   lower   with   the   amalgam    forming 
the  tilling  on  the  Bide  of  the   root.      In  such  a  case,  the  pin  sup- 


m 


SHAPING   TEETH  AXD  ROOTS  FOR  CROWN-WORK. 


43 


porting  the  crown  should  be  tapered  at  the  end,  and  inserted 
in  the  canal  as  deeply  as  possible  beyond  the  end  of  the  tube. 
Additional  strength  is  thus  obtained  by  a  distribution  of  the 
leverage  along  the  whole  line  of  the  root. 

When   a   gold   cap-crown  is  to  be  adjusted  on  a  badly  broken- 
down  tooth  or  root,  a  post  of  silver  or  iridio-platinum  wire  should 
be  formed  to  tit  the  root-canals  as  shown  in  Figs.  26,  27,  and  28^. 
avith  ■t^pmec^xt£_db:cr.SQid^yf>d-nrrn^ymse^     The  post  should  then 


Fig.  26. 


Ul 


Fig.  27. 


r\ 


Fig  28. 


be  barbed  and  the  point  first  fastened  in  the  root  with  a  little 
oxyphosphateyancl  the  crown  portion  built  down  about  two-thirds 
of  its  length*  with  a  quick-setting  amalgam.  This  when  hard 
should  be  shaped  and  then  roughened  to  furnish  a  better  at- 
tachment for  the  cement  with  which  the  crown  is  set.  Screws 
can  be  /sed  as  posts  to  support  the  amalgam  if  preferred.  As 
the  artificial  crown  completely  covers  all  the  amalgam,  the 
existmg  prejudice  against  its  use  cannot  apply  to  this  method. 


PAET    11. 


ARTIFICIAL  CROWN-WORK. 


ARTIFICIAL   CROWN-WORK 

Artificial  crown-work  affords  extensive  facilities  for  restoring 
the  crowns  of  natural  teeth,  and  furnishes  means  of  support  for 
bridge-work. 

Two  general  systems  are  presented, — the  porcelain  and  the 
gold.  The  porcelain  system  includes  porcelain  crowns  with  me- 
tallic attachments,  with  or  without  collars,  and  the  gold  system 
gold  crowns  with  porcelain  fronts. 


47 


THE   PORCELAIN   SYSTEM. 


CHAPTER   I. 


PORCELAIN    CROWNS. 


Porcelain  crown-work  is  practiced  by  many  dentists  almost 
exclusively,  excepting  only  the  occasional  insertion  of  a  gold 
cap-crown  on  a  posterior  tooth.  The  reasons  for  this  are,  the 
intricate  character  of  the  construction  of  gold  crowns,  and  the 
objection  to  crowns  with  bands  or  collars. 

The  advocates  of  the  all-porcelain  system  claim  for  it  natural 
appearance,  restoration  of  contour,  strength,  and  cleanliness, 
together  with  simplicity  of  construction  and  easy  adaptation  and 
attachment  to  the  root,  to  which  the  crown  is  hermetically  sealed. 

Porcelain  crowns  are  made  in  two  general  styles.  In  one  the 
crown  is  attached  to  the  root  by  a  pivot,  post,  or  screw,  one  end 
of  which  is  cemented  in  the  root  and  the  other  in  the  crown. 
Such  are  the  ]>onwill,  Gates,  Foster,  How,  and  Howland  crowns. 
In  the  other  style,  one  end  of  the  pivot,  or  post,  is  baked  in  the 
porcelain  when  the  crown  is  made,  and  the  other  end  cemented 
into  the  root  when  the  crown  is  adjusted.  The  Logan,  Brown, 
and  new  Richmond  are  of  this  class. 

Special  advantages  are  claimed  for  each  of  these  several  forms 
of  crowns.  A  general  knowledge  of  the  different  methods  is 
therefore  essential  to  determine  the  adaptation  of  each  to  the 
requirements  of  a  ease. 

The  preparatory  treatmenl  of  the  roots  respecting  the  process 
of  grinding,  trimming,  and  shaping  is  nearly  the  same  tor  all 
porcelain  crowns.    Exposing  the  end  of  the  root,  by  pressingthe 

48 


THE  BON  WILL  CROWS. 


49 


gum  away  from  it  with  gutta-percha  preliminary  to  the  opera- 
tion, will  greatly  assist  the  operator,  by  enabling  him  to  avoid 
accidental  laceration  of  the  adjoining  membranes,  and  the  annoy- 
ance attending  their  bleeding,  besides" permitting  him  to  care- 

lly   study   the    adjustment   and    cementation    of   the    crown. 

rowns  in  which  the  post  is  cemented  will  first  he  described. 

THE    BONWILL   CROWN. 

This  crown,  being  one  of  the  first  introduced  in  improved 
porcelain  crown-work,  has  been  very  extensively  used.  The 
process  of  its  adjustment  and  insertion  is  explained  in  a  lengthy 
article  by  its  inventor  and  advocate,  Dr.  W.  G.  A.  Bonwill,  from 
which  the  following  is  presented  : 

"  These  all-porcelain  crowns  have  three  distinctive  features  : 
a  concave  or  countersunk  base;  a  triangular  opening  from  the 
base  to  a  point  at  or  near  the  cutting-edge  of  the  incisors,  the 
base  presenting  to  the  labial  surface  (at  its  upper  portion  this 
groove  is  enlarged);  a  peripheral  margin  or  border  resting 
perfectly  flat  on  the  root,  the  concavity  of  the  base  on  the  palatal 
side  being  at  a  much  more  acute  angle  than  on  the  approximal 
sides.  An  anchorage  is  made  in  the  incisors  by  a  depression  or 
undercut  between  the  labial  and  palatal  surfaces,  opening  on  the 
latter.  In  the  bicuspids  aud  molars  the  retaining-pits  are  nearer 
the  grinding-surface. 


Fig.  29.      Fig.  30. 


Fig.  31. 


Fig.  32. 


Fig  33.       Fig.  34.     Fig.  35. 


Fig.  29. — Sectional  view  of  an  incisor  crown,  from  mesial  side,  showing  the  undercut  at  the 
point  opening  on  palatal  surface,  the  conical  base,  and  the  opening  from  the  same  to  the  retain- 
ing-grooves,  with  the  exact  relations. 

Fig.  30. — Palatal  view  of  same  tooth,  a  is  the  external  opening  for  egress  of  alloy  and  for 
packing  around  the  pin.  The  dotted  lines  show  the  recess  or  undercuts  on  the  mesial  and  distal 
sides  and  near  the  point  for  retaining  the  crown,  and  its  relation  with  the  conical  base. 

Fig-  31.— Grinding-surface  view  of  a  superior  molar  with  the  countersunk  pin-holes  on  the 
buccal  and  palatal  sides. 

Fig  32. — Same  view  of  an  inferior  molar  with  the  pin-holes  on  the  mesial  and  distal  sides. 

Figs.  33  and  34. — Sectional  views  of  a  molar  and  a  bicuspid  crown,  showing  the  countersinks 
and  their  relations  with  the  conical  base. 

Fig.  35. — Sectional  view  of  an  incisor  root,  showing  the  retaining-cuts  made  by  the  wheel-bur 
shown  in  Fig.  42. 

4 


50 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


"  The  concave  base  of  the  crown  prevents  the  amalgam  from 
escaping  under  the  heavy  pressure  exerted  to  force  it  into  posi- 
tion, and  in  impacting  the  amalgam  and  expressing  the  mercury. 
It  allows  of  a  dense  body  of  material  around  the  metallic  pin, 
giving  the  equivalent  of  a  pin  the  whole  diameter  of  the  base 
of  the  crown.  It  leaves  no  joint,  the  crown  and  root  being 
continuous.  The  amalgam  is  so  thoroughly  hardened  at  once 
by  impaction  in  the  double  concave  of  crown  and  root  as  to 
make  a  very  firm  operation.  It  prevents  any  possibility  of  the 
crown's  twisting  upon  the  pin  and  root.  In  the  event  of  fracture 
of  the  crown,  the  convex  surface  of  amalgam  on  the  root  makes 
Fio.  36.         Fio.  38.  Fig.  39.  Fig.  40.  Fig.  41.        Fig.  42. 

©c 
Fio.  37. 


Fig.  36.— End  view  of  a  canal  prepared  for  the  improved  combination-metal  pin. 

Fig.  37.— End  view  of  same  canal  as  in  Fig.  36,  prepared  for  a  triangular  pin.  showing  how 
much  more  of  the  mesial  and  distal  surfaces  have  been  cut  away  from  it  than  in  Fig.  36  for  the 
improved  pin. 

Pig.  3-*. — Sectional  view  of  an  incisor  crown  and  root,  with  the  improved  pin  in  its  relative 
position  to  each,1  with  the  depressions  made  by  wheel-bur. 

Fig.  39. — Sectional  view  of  a  superior  molar,  with  the  large  angular  pin  in  palatal  root  and 
two  square  pins  in  the  buccal  roots,  one  being  shorter  and  not  passing  through  the  crown. 

Fig.  40.— Block  of  a  molar  and  bicuspid,  showing  the  countersunk  holes  for  pins  in  the  molar, 
and  the  hole  in  the  mesial  side  of  the  second  bicuspid  where  a  pin  is  alloyed  in  and  set  into  a 
decayed  cavity  in  the  distal  surface  of  the  first  bicuspid,  being  held  upon  the  molar  roots  and 
attached  to  the  bicuspid  by  the  alloy. 

Fit.'.  41.— Side  and  end  view  of  the  largest  size  angular  combination-metal  pin  with  the 
stamped  serrations.5  The  square  pins  are  without  serrations  and  double-pointed,  made  of  the 
-.inn'  metal  and  of  equal  thickness  throughout. 

Fig.  42.— I'h  ■  smallest-sized  wheel-bur  for  grooving  the  canals  for  anchoring  the  pin  and  alloy. 

'Tin-  sectional  views  of  the  incisor  and  molar,  giving  the  relative  position  of 
the  pin-  in  the  crowns  and  roots,  should  show  pins  of  larger  size.  The  pins  as 
furnished  Bhould  be  Bled  down  but  little.  It  is  not  absolutely  necessary  that  so 
many  serrations  Bhould  1";  made  in  the  canals  by  the  wheel-bur  for  retaining  the 
amalgam  and  pin  as  are  shown  in  the  sectional  view  of  the  root  of  an  incisor. 
While  no  serration-  are  shown  in  the  roots  of  the  molars,  it  is  understood  that  all 
the  canal-  rnu<t  have  the  serrations.  The  square  pins  in  the  canals  need  no  serra- 
tions.    At  the  point  where  they  occupy  the  countersink  in  the  crowns,  make  two 

or  three  very  slight  cuts  on  the  edges  with  a  sharp  file.    The  end-  can  be  left  blunt. 

'These  pin-  are  now  made  without  serrations.  When  amalgam  i-  used  for 
securing  them,  they  become  amalgamated  and  firmly  united. 


THE  BON  WILL  CROWN.  -0\ 

the  substitution  of  a  new  crown  an  easy  operation.  It  enables 
the  operator  to  tit  the  crown  in  much  less  time:  it  allows  a 
proper  position  to  be  given  to  the  pin.  with  less  danger  of  frac- 
ture therefrom  ;  it  permits  of  a  larger  quantity  of  amalgam  in 
the  crown,  and  is  capable  of  bearing  greater  strain  ;  it  makes 
the  permanent  success  of  the  operation  probable,  from  the  fact 
that  it  is  absolutely  jointless,  and  secures  immediate  solidity, 
even  while  the  amalgam  is  semi-plastic.  These  crowns  are 
capable  of  resisting  the  force  of  biting  or  mastication,  because 
they  are  supported  nearly  to  the  cutting-edge  or  grinding-sur- 
face,  the  triangular  opening  from  the  concave  base  nearly  to  the 
cutting-edge  allowing  the  pin  to  be  imbedded  in  the  labial  face 
of  the  crown  where  there  is  the  greatest  amount  of  porcelain. 

"The  amalgam  to  be  used  as  the  medium  of  union  must  set 
quickly  and  be  very  hard.  Thus  far  I  have  found  nothing  better 
than  the  alloys  I  have  specially  prepared  for  this  line  of  work, 
and,  though  they  are  costly,  the  superior  results  obtained  by 
their  use  amply  repay  the  cost.  I  use  No.  1  generally.  If  mixed 
thick,  it  will  set  so  quickly  that  the  operator  must  work  rapidly 
to  prevent  its  being  wasted.  In  incisor  cases  I  use  No.  3  at  the 
gum  line  and  make  a  close  joint. 

"In  preparing  the  canal,  use  first  a  small-sized,  spear-shaped 
drill,  carefully  following  the  natural  channel.  Then  follow  with 
a  larger  one,  taking  care  not  to  cut  through  the  root  near  the 
apex.  On  the  mesial  and  distal  sides  cut  away  but  little,  as  there 
is  where  fractures  are  most  liable  to  occur.  The  canal  can  be 
very  tapering  and  yet  hold  the  pin.  There  need  be  but  very 
little  space  around  the  pin.  By  all  means  save  all  the  walls  of 
the  root  possible.  The  smallest-sized  wheel-bur  may  be  used  to 
make  an  interrupted  female  thread  at  various  points  along  the 
canal  to  hold  the  amalgam. 

"  If  the  patient  exposes  the  gums  much  in  speaking  or  smiling, 
the  root  may  be  cut  down  with  the  bur  or  corundum-wheel  be- 
yond the  free  edge  to  conceal  the  joint.  With  bicuspids  and 
molars  it  is  not  necessary  to  go  below  the  gum;  a  joint  well 
made  will  not  be  observed,  and  the  strength  of  the  root  will  be 
preserved.  If  the  root  is  decayed  below  the  gum,  after  removing 
the  softened  parts,  till  it  with  alloy. 


50  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

••  [l  is  no1   necessary  that  the  face  of  the  root  should  be  flat; 
it  may  be  either  concave  Or  convex,  according  to  indications. 

••  It  is  advantageous  to,  lake  an  impression  and  'bite'  of  the 
root,  and  make  a  model  and  articulation  in  plaster. 

"The  crown  to  he  inserted  should  he  inspected  closely,  as  the 
retaining  undercut  in  the  incisors  and  the  depressions  in  the  bi- 
cuspids and  molars  may  not  be  well  defined.  Ef  not,  the  crowns 
an-  liable  to  work  loose.  If  the  base  has  been  ground  off  in  fit- 
ting:, tli'-  edges  should  be  beveled  again  to  a  fine  margin  with  a 
corundum-point.  The  crown  should  be  fitted  to  the  root  in 
the  mouth,  not  to  the  plaster  cast.  The  articulation  should  be 
clear,  to  avoid  displacement.  The  pin  should  be  as  large  as  the 
previously  prepared  canal  will  admit.  The  pin  must  in  every 
case  be  fitted,  and  in  fitting  it  file  only  on  the  plain  sides.  Leave 
the  end  -harp,  to  offer  the  least  resistance  in  passing  through  the 
amalgam.  The  end  of  the  pin  to  be  passed  into  the  crown  needs 
very  little  alteration.  The  crown  being  open  on  the  palatal  sur- 
face of  the  incisors,  permits  a  blunt-pointed  pin  to  go  up  to  its 
place.  The  middle  of  the  pin  should  not  be  interfered  with  if  it 
<-an  be  avoided.  It  is  well  to  cut  the  pin  a  little  short  for  in- 
cisors, as  it  may  not  get  pushed  entirely  up  in  the  root  through 
the  amalgam.  Small  square  pins  are  used  in  the  bifurcated 
roots  of  bicuspids  and  in  the  buccal  roots  of  molars.  They  can 
b.-  sharpened  at  both  ends,  but  the  outer  end  will  not  require  so 
much  sharpening.  The  palatal  roots  of  molars  will  generally 
take  one  of  the  largest  thick:  pins,  with  one  square  pin  in  the 
largest  and  most  accessible  buccal  root.  Each  canal  should  have 
a  pin.  if  the  canal  can  be  reached  and  properly  prepared  to  receive 
it.  even  though  the  pin  has  to  be  so  short  as  not  to  pass  through 
the  hole  in  the  crown.  If  it  enters  the  countersunk  base  it  will 
support  the  root.  The  lower  molars  will  require  two  ot  the 
largest-sized  pins.  As  the  support  of  the  root  is  dependent 
upon  the  size  of  the  pin  and  the  depth  to  which  it  is  inserted, 
1  teeth  should  have  tin;  yryy  largesl  thick  pin.  If 
the  root  is  thin  on  the  mesial  and  distal  sides,  the  thin,  angular 
pin  i>  to  be  preferred.  Ordinarily  these  large  pins  do  not  have 
to  be  bent,  [f  necessary,  it  had  better  be  done  with  a  hammer, 
and  before  the  mercury  touches  them.     The  pin  should  have 


THE  BON  WILL  CROWN.  53 

free  movement  in  both  root  and  crown.  Should  it  be  discovered 
that  the  pin  is  too  long  after  it  has  been  packed  in  the  root,  it 

•  •an  be  cut  oft*  with  sharp  forceps,  pressing  them  up  against  the 
pin  to  prevent  displacement.  The  pin  can  be  sharpened  subse- 
quently with  the  corundum-wheel. 

"To    insure    an    amalgamation   of  the  pin   with  the  filling-, 
brighten  the  surface  of  the  former  before  inserting. 

"The  roots,  crown,  and  pins  being  in  readiness  and  arranged 
on  the  table,  so  that  no  mistake  may  occur  from  getting  the  pin 
in  the  wrong  position,  and  the  appliances  necessary  for  the  opera- 
tion being  at  hand,  the  alloy  preferred  should  be  mixed  a  little 
thinner  than  if  intended  for  a  filling,  especially  where  the  root 
has  a  long  canal.  The  shorter  the  canal,  the  thicker  the  amal- 
gam may  be  mixed.  Mix  only  enough  at  one  time  for  one  root. 
Put  enough  amalgam  in  the  canal  to  nearly  fill  it,  but  do  not 
pack  it ;  force  a  steel  pin  made  for  the  purpose,  of  about  the 
same  size  as  the  pin,  to  make  way  for  the  easier  insertion  of  the 
latter.  Then  grasp  the  pin  with  suitable  forceps,  and  carefully 
but  steadily  press  it  up  to  its  destination.  If  you  cannot  suc- 
ceed in  doing  so,  remove  it,  and  again  use  the  steel  pin.  When 
in  place,  use  an  instrument  with  a  point  small  enough  to  pass 
between  the  pin  and  the  root,  and  pack  by  tamping  the  amalgam 
around  it.  A  piece  of  bibulous  paper  placed  over  the  point  of 
the  instrument  will  assist  materially  in  carrying  the  amalgam 
before  it.  Before  the  amalgam  has  become  too  hard,  replace  the 
crown  to  determine  if  the  pin  is  in  proper  position ;  if  not,  it 
can  be  crowded  to  one  side  or  the  other  with  the  tamping-tool. 
Should  the  pin  be  found  to  be  rather  long,  it  can  be  ground  off 
with  the  corundum-wheel,  holding  it  meanwhile  with  the  forceps. 
Xo  attempt  should  be  made  to  bend  the  pin  after  it  has  been 
amalgamated,  for  fear  of  breaking  it.  If  any  amalgam  has  been 
left,  and  it  is  still  plastic,  it  may  be  packed  around  the  pin  at  the 
base  of  the  root,  using  the  bibulous  paper  as  before  directed.  If 
not,  mix  again  to  complete  the  operation.  Bank  up  the  amal- 
gam on  the  root  high  enough  to  fill  the  base  of  the  crown.  The 
crown  should  now  be  tried  on,  and  forced  home  with  an  adjuster 
adapted  to  the  case,  removing  the  surplus  amalgam  if  too  much, 
or  adding  if  not  enough.     Remove  and  dry  the  crown,  and  till 


54  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

up  simply  the  undercut  cavity  near  the  cutting-edge  if  an  incisor, 
or  the  depressions  in  the  crowns  of  bicuspids  or  molars,  allowing 
a  \  ery  little  to  extend  into  the  cervical  base.  Now  force  it  home 
with  the  adjuster.  It  requires  considerable  force  to  set  one  of  these 
crowns  according  to  directions, — a  force  which  cannot  be  applied 
witha  mallet  without  danger  of  loosening  or  displacing  the  crown. 
Steady  pressure  with  slight  rotation  will  carry  the  crown  into 
place,  if  the  amalgam  is  not  too  hard  or  there  is  not  too  much  of 
it.  I  would  advise  you  not  to  attempt  to  set  a  crown  without  an 
adjuster  or  its  equivalent.  Free  mercury  will  be  squeezed  out  on 
the  palatal  surface,  which  should  be  wiped  oft'.  Xow  hold  the 
crown  in  place  with  the  fingers,  with  the  bibulous  paper  under 
the  tamping-instrument,  and  consolidate  the  amalgam  around  the 
point  of  the  pin  in  the  crown,  absorbing  any  free  mercury  which 
appears  there.  The  excess  of  alloy  at  the  joint  must  now  be  re- 
moved, care  being  taken  to  press  the  crown  up  while  this  is  being 
done.  The  amalgam  packed  around  the  pin  in  the  crown  on  the 
palatal  side  should  be  as  stiff  as  may  be  to  work  readily.  It  is 
well  to  leave  over  some  of  the  first  mixing  for  holding  the  pin, 
and  this  will  be  about  right  for  consolidating  about  this  point. 

"If  in  a  bicuspid  or  molar  crown  the  pin  should  come  so  far 
through  as  to  interfere  with  articulation,  it  may  be  ground  off 
with  the  corundum-wheel  while  the  crown  is  firmly  held. 

"The  case  can  now  be  dismissed,  with  directions  for  the  patient 
to  return  the  nexl  day,  in  order  to  make  sure  that  the  articula- 
tion i-  correct  and  to  dress  off  the  joint  between  the  crown  and 
root,  which  may  he  done  with  a  small  round-headed  bur. 

"  There  are  some  eases  in  which  the  root  cannot  he  tilled  with 
anything;  if  in  a  molar,  the  pulp-chamber  can  he  relied  upon  to 
hold  a  headed  pin  or  pins.  When  a  tap-hole  is  required  in  the 
root  it  can  be  made  low  down  and  at  an  acute  angle,  and  the 
amalgam  packed  around  the  root-canal  above  the  tap. 

"Should  an  artificial  crown  be  broken,  another  can  easily  he 
substituted,  by  burring  oil'  any  excess  of  amalgam,  and  using 
fresh  amalgam,  mixed  thin,  to  allow  of  ready  adjustment. 

"Two  crowns  can  he  inserted  on  the  rool  of  one  large  molar 
with  tie-  assistance  of  the  decayed  approximal  surface  of  an 
adjacent  tooth  (see  Fig.  I").'" 


THE  HOW  CROWNS  AND  METHODS. 


55 


Fig.  4." 


THE    HOW    CROWNS    AND    METHODS. 

These  crowns  are  the  invention  of  Dr.  W.  Storer 
How.  There  arc  two  styles, — tour-pin  crowns  for 
incisors,  cuspids,  and  bicuspids,  and  porcelain 
dovetail  crowns  for  bicuspids  and  molars.  Each 
form  embraces  some  novel  features.  Dr.  How's 
methods,  being  general  in  application,  are  used  in 
inserting  other  forms  of  crowns. 

The  following  are  Dr.  How's  descriptions  and 
illustrations  of  his  methods  and  crowns: 


Fig.  43.         Fig.  44.      Fig.  47.     Fig.  48.     Fig.  49.    Fig.  50. 


Fir;.  46. 


"  The  Four-Pin  Crown.— -The  difficulties  and 
uncertainties  in  mounting  artificial  tooth-crowns 
on  roots,  by  either  old  or  new  methods,  led  me  to 
a  careful  study  of  the  problem,  and  resulted  in  a 
nearly  simultaneous  devising  of  several  new  forms 
of  crowns  and  appliances  for  setting  them,  as  well  as 
a  perfected  method  of  performing  the  operation  of 
fixing  a  peculiar  screw-post  (Fig.  43)  in  a  root,  and 
also  a  novel  process  of  attaching  the  crown  to  the 
post.  At  present  I  will  describe  simply  the  four- 
pin  crown  (Fig.  44)  and  the  successive  steps  to  be 
taken  in  mounting  it. 

"  1.  When  the  root  is  in  proper  condition  for  mounting, 
measure  the  depth  of  the  canal  by  means  of  the  canal  plugger 
and  its  flexible  gauge  (Fig.  45),  and  fill  the  canal  at  and  a  short 
distance  from  the  apex  of  the  root,  keeping  the  gauge  at  position 


I 


56 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


to  show  the  full  length  of  the  canal  and  also  the  distance  to 
which  it  has  been  tilled. 

••  2.  Cut  off  the  root-crown  with  excising  forceps  and  a  round 
file,  down  to  the  gum  margin,  and  with  barrel  bur  Xo.  241  cut 
the  labial  part  of  the  root  fairly  under  the  gum  without  wound- 
ing it. 

••  3.  Set  gauge  on  a  Gates  drill  (Fig.  46)  to  one-half  the  gauged 
depth  of  the  canal,  and  drill  to  that  depth. 


Fig.  51. 


Fig.  52. 


Fig.  53. 


Fig.  55. 


Fig   54. 


"  4.  Set  the  twist-drill  in  its  chuck  (Fig.  47)  to  project  the  same 
length  as  the  Gates  drill,  and  drill  the  root  to  exactly  that  depth. 

"  5.  Enlarge  the  mouth  of  the  canal  one-sixteenth  of  an  inch 
deep  all  around  to  near  the  margin  of  the  root,  as  shown  in 
Fig.  48,  using  square-end  fissure-bur  No.  59,  and  then  with 
oval,  X<>.  94,  undercut  a  groove  lingually  and  at  the  sides. 

"6.  It'  the  rubber-dam  is  to  be  used  for  a  gold  or  plastic 
backing,  put  it  now  over  the  root  with  Hunter's  root-clamp, 
also  over  the  adjacent  teeth,  and  thoroughly  dry  the  canal. 

••7.  8e1  tin-  tap  in  its  chuck  (Fig.  49)  a  trifle  less  in  length 
than  the  drill,  oil  it,  and  carefully  tap  the  root  to  the  gauged  depth. 

"8.  [nsert  the  post  in  its  chuck  (Fig.  50)  to  the  exact  gauge 
of  the  tap,  and  turn  the  thumb-screw  down  hard  on  the  end  of 
the  post,  then  screw  the  post  into  the  root,  release  the  thumb- 


THE  HOW  CROWNS  AND  METHODS.  57 

Bcrew,  unscrew  the  chuck  a  halt-turn,  bend  the  post  until  the 
chuck  stands  in  center  line  with  the  adjoining  teeth,  and  unscrew 
the  chuck  from  the  post.  , 

"  9.  Slit  the  rubber  back  from  adjacent  teeth,  tucking  the 
flaps  out  of  the  way,  bo  that  the  occlusion  may  be  tried,  the  post 
excised  and  ground  off  until  the  teeth  close  clear  of  the  post. 

"  10.  Try  the  crown  on  the  post,  and  with  disk  F  grind  the 
rib  between  the  neck  pins  until  the  crown  is  labially  flush  with 
the  root  margin,  using  the  disk  dry  and  cutting  a  little  at  a  time 
until  exactly  flush. 

"  11.  Take  the  crown  and  place  the  mandrel  (Fig.  51)  between 
the  pins  just  as  the  post  is  to  be,  and  with  the  pliers  (Fig.  52) 
bend  the  pins  carefully  over  the  mandrel,  cutting  off  the  pins  if 
too  long  to  be  pinched  in  on  the  mandrel  at  the  sides,  observing 
that  the  pin  nearest  the  cutting-edge  is  first  to  be  bent  (Fig.  53), 
and  the  opposite  pin  bent  below  it  on  the  mandrel,  and  so  with 
the  others  (Fig.  54). 

"•12.  Slip  the  crown  over  the  post,  try  occlusion,  and  with 
the  post-chuck  bend  the  post  until  the  crown  is  properly  aligned 
with  the  teeth,  then  with  a  stump  corundum-wheel  No.  3  grind 
the  neck  of  the  crown  to  a  close  labial  fit  with  the  root,  fitting 
only  the  portion  to  be  concealed  by  the  gum,  leaving  narrow 
gaps  at  the  sides  to  be  filled  by  the  backing  between  crown  and 
root  (Fig.  55). 

"13.  Grind  cutting-edge  for  occlusion  and  relation  to  the 
other  teeth,  and  be  sure  that  the  opposing  tooth  does  not  strike 
the  crown,  the  post,  or  the  pins. 

"  14.  Fix  the  crown  on  the  post  by  pinching  the  pins  into  the 
screw-threads  in  the  post  with  the  special  pliers  for  that  purpose. 

"  15.  Finally,  pack  the  backing  of  gold,  or  cement,  or  amal- 
gam, or  Wood's  metal,1  or — for  temporary  backing  while  treating 
abscess — gutta-percha,  into  all  the  crevices  around  the  post  and 
behind  and  under  the  pins,  and  between  the  crown  and  the 
root ;  contour  and  finish  thoroughly,  so  that  no  ledge  or  other 
imperfection  can  be  found. 

"  Fig.  56  shows  in  vertical  mid-section  an  incisor  crown 
mounted  on    a  root;    the  blackened   portions   of  the  backing 

1  Wood's  metal  suggested  by  Prof.  J.  Taft. 


:,s 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


serving  to  define  clearly  the  locking-hold  of  the  backing  on  the 
screw-post,  the  crown-pins,  and  the  root  recess. 


Pia  50. 


Fig.  57. 


Fio.  58. 


u  Fig.  57  shows  in  perspective  a  cuspid  crown  ready  to  be 
slipped  over  its  post,  and  also  a  cuspid  crown  ready  for  its  post 
in  the  bicuspid  root,  which  has  its  lingual  cusp  remaining;  and 
Fig.  58  shows  these  crowns  on  their  posts  awaiting  the  com- 
pleting or  contour-backing. 

••  When  it  is  desired  to  contour  the  backing  of  a  cuspid  crown 
to  form  an  inner  cusp,  or  to  adapt  a  cuspid  or  incisor  crown  for 
masticating  uses,  the  pins  may  be  twisted  together  over  the  man- 
drel, and   again  twisted  tightly  over  the  post  as  in  Fig.  59;  but 


Fig.  59. 


Fig.  60. 


Fig.  61. 


in  some  cases  it  may  be  better  to  bend  the  neck-pins,  as  in  Fig. 
60,  instead  of  twisting  them.  In  all  cases  the  benl  pins  are  to 
be  pinched  quite  bard  over  the  mandrel  and  post,  so  thai  the 
b  srratioufi  of  the  pliers  will  roughen  the  pins  to  prevent  their 
being  pulled  through  the  backing,  which  should  also  be  carefully 
condensed  around  the  pins  and  post. 

•■  When  the  root  is  much  decayed,  the  bottom  of  the  cone- 
shaped  cavity  may  be  drilled  and  tapped  to  the  depth  of  a  six- 


THE  HOW  CROWNS  ASD  METHODS. 


59 


ith  of  an  inch,  and  the  post,  thus  anchored,  may  be  further 
ired  by  cement  in  the  grooved  walls  of  the  cavity  and  around 
the  p<»st  (Fig.  61). 

"The  Bcrew-posta  are  made  of  crown  metal  an  alloy  devised 

for  the  purpose  in  order  t>»  obtain  a  stiff  post  that  will  permit 
the  cutting  of  the  peculiar  and  extremely  accurate  thread  form,  d 
upon  it,  and  which  will  not  amalgamate  or  he  otherwise  affected 
by  any  backing-material  that  may  be  used.  Of  course  platinum 
or  platinum  alloyed  with  iridium  may  he  employed  for  posts, 
but  the  crown  metal  is  in  every  way  superior. 


Fig.  62. 


Fig.  63.     -   Fig.  64. 


Fig.  65. 


Fig.  66. 


••  There  are  some  cases  of  a  class  which  has  hitherto  presented 
difficulties  that  may  now  he  easily  overcome  by  grinding  the 
post  flat  on  the  crown  side  after  it  has  been  set  and  bent  in  the 
root  (Fig.  62).  so  as  to  be  clear  of  the  occluding  tooth ;  and  then 
the  crown-pins  may  be  bent  over  the  reduced  post,  the  crown 
fitted  and  ground  to  clear  the  opposing  tooth  (Fig.  63),  and  the 
backing  added  in  completion. 

••  A  similar  case,  in  which  the  opposing  tooth  and  a  proper 
alignment  require  an  oblique  bending  of  the  pins,  is  seen  in  Fig. 
64.  while  the  reverse  arrangement  of  parts  is  shown  in  Fig.  65. 
The  crown  is  thus  seen  to  be  adapted  to  a  wide  range  of  adjust- 
ments, because  its  paint  of  contact  with  the  root  is  at  the  labial 
portion  of  the  neck,  on  which  as  on  a  hinge  the  crown  may  be 
swung  oat  or  in  (Fig.  66,  dotted  lines),  over  an  arc  of  at  least 
>ixty  degrees,  at  any  point  of  which  it  may  be  quickly  and  firmly 


f 


60 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


fixed.  The  labio-cervical  junction  is  made  just  under  the  gingi- 
val margin,  and  I  usually  interpose  a  thin  layer  of  cement,  amal- 
gam, or  gutta-percha,  or  a  narrow  ribbon  or  several  large  blocks 
of  soft  gold  :  the  joint  always  to  be  made  carefully  smooth,  and 
hid  from  view  under  the  free  margins  of  the  gums." 

'/'A.  Porcelain  Dovetail  Tooth-Crown. — These  crowns  are  de- 
signed for  the  roots  of  bicuspids  and  molars  only,  and  the  process 
of  mounting  them  may  be  very  briefly  described. 

•■  Fig.  67  shows  the  roots  of  an  inferior  molar  after  the  apical 
portions  have  been  filled,  the  neck  recessed,  the  canals  drilled 
and  tapped,  and  two  How  screw-posts  firmly  fixed  therein,  the 
ends  of  the  posts  having  been  pinched  towards  each  other  by 
mean-  of  a  pair  of  pliers,  so  that  they  will  go  through  the  cen- 
tral opening  in  the  crown  (Fig.  68).     This  opening  is  of  a  dove- 

Fig.  67.  Fio.  68.  Fig.  09.  Fig.  70.         Fig.  71.  Fig.  72. 


tail  form,  as  shown  in  cross-section  by  Fig.  69,  where  the  crown 
is  seen  in  place  over  the  posts  on  the  root.  It  is  thus  made 
obvious  that  the  crown  may  be  easily  put  on  and  oft'  the  root  in 
the  process  of  fitting  the  crown-neck  to  the  root-neck,  and  also 
that,  for  occlusion,  the  crown  may  be  ground  low  on  any  or  all 
Bides  without  destroying  the  dovetail  function  of  the  central 
cavity.  When  the  fitting  is  completed,  and  the  crown  cut  so 
Bhoii  as  to  he  ..'.,  of  an  inch  distant  from  the  occluding  tooth, 
amalgam  i-  packed  into  the  neck  recess,  around  the  posts,  and 
thinly  over  the  cervical  margin  of  the  root,  the  crown  put  in 
place,  and,  with  thumb  pressure,  firmly  seated.  Then  test  the 
occlusion,  and  complete  the  operation  by  packing  amalgam  into 
tie-  crown  opening,  which  will  permit  the  forcing  of  the  amalgam 
in  all  directions,  to  insure  a  linn  hase  for  the  crown,  anil  its 
secure  dovetail  attachment  to  the  posts,  as  shown  by  Fig.  69. 
•■The  bicuspid  crown  (Figs.  7<)  and  71)  is  similarly  mounted, 

B8  may   he    Been    in   Fig.  72,  cr088-8ection ;    tie'   same  crown    and 


THE  HOW  CROWNS  AND  METHODS. 


til 


root  Wing  shown  in  contour  by  Fig.  73.  In  some  instances  this 
bicuspid  crown  may,  like  the  Foster  crown,  be  secured  by  a 
headed  screw,   as  shown   in    Fig.  74.      The  root   having   been 


Fig.  75. 


Fig.  76. 


drilled  and  tapped  and  recessed,  and  the  crown  properly  fitted 
and  articulated,  the  screw  is  put  through  the  crown,  amalgam 
packed  in  the  crown-groove  and  around  the  screw,  which  is  then 
inserted  in  the  root,  and  the  crown  pressed  hard  into  its  place. 
The  -crew  is  then  turned  into  the  position  shown  in  Fig.  74, 
thus  compressing  the  amalgam  or  cement  in  both  recess  and 
groove,  after  which  the  screw-head  may  be  covered  with  amal- 
gam, cement,  or  gold,  as  desired. 

Fig.   77 


"  As  a  preferable  mode,  however,  the  screw-post  may  first  be 
fixed  in  the  root,  the  crown  adjusted  over  the  post,  amalgam 
packed  on  the  root  and  around  the  post,  the  crown  seated  firmly, 
more  amalgam  packed  in  the  crown  cavity  around  the  post,  and 
then  a  nut  screwed  on  the  post,  as  shown  in  Fig.  75.  In  all  the 
sectional  cuts  cement,  amalgam,  or  gutta-percha  is  to  be  under- 
stood as  filling'  the  cavities  in  the  conjoined  roots  and  crowns. 


62 


ARTIFICIAL  CROWS-  ASD  BRIDGE- WORK. 


Fio.  78. 


"Fig.  76  shows  in  contour  a  dovetailed  crown  mounted  on  a 
superior  molar  root  in  the  manner  shown  by  Fig.  69.  It  is 
obvious  that  the  crown  of  Fig.  69  might  be  ground  quite  down 
to  the  post-ends,  and  yet  be  firmly  held  by  the  dovetail  sides  of 
the  central  cavity." 

THE  GATES  CROWN. 

The  Gates  crown  has  become  identified  with  the  Bon  will, 
owing  to  its  similarity  (Fig.  77).  It  is  usually  attached  to  the 
root  by  a  metallic  screw  manufactured  for  the  purpose,  such" 
as  is  illustrated  in  Fig.  78,  instead  of  the  Bonwill 
pin.1  The  screw  is  first  inserted  in  the  root  and  the 
amalgam  [tacked  around  it.  In  nearly  all  roots,  at  a 
reasonable  distance  up  the  canal,  a  suitable  place  for 
fastening  the  end  of  the  screw  can  be  found.  Too 
much  force  must  not  be  applied  in  its  insertion,  as  a 
root  is  easily  split.  In  bicuspid  and  molar  crowns  nuts 
are  used  on  the  screws,  which  fit  slots  in  the  grin  ding-surface  of 
the  porcelain.  They  are  screwed  into  the  amalgam  or  cement, 
and  covered  with  it  in  the  process  of  cementation  of  the  crown. 
When  it  is  desirable  or  necessary  to  construct  a  screw  for  a 
special  case,  it  should  be  made  of  iridio-platinum  wire  (as  this 
alloy,  being  hard,  will  well  maintain  the  edge  of  the  thread). 
Gold  is  unsuitable,  owing  to  the  action  upon  it  of  the  mercury 
in  th<-  amalgam,  even  though  the  amalgam  is  used  "dry." 

In  forming  ;i  screw  a  coarse-thread  screw-plate  should  be  used. 
The  thread-  of  most  screws  are  cut  too  fine. 

THE   FOSTER    CROWN. 

The  Foster  crown  (Fig.  79),  which  in  genera]  form 
Fio.  79, 

to  a  crown  introduced  by  Dr.  II.  Lawrence,  of  Philadelphia,  in 
L849,  also   resembles-the   Bonwill,  but  has  less  concavity  at  the 

1  Dr.  Qates  originally  used  a  double-ended  <>\  ul-shnped  screw.    The  H<>w  screws 
(sec  |  nanufcetared  by  The  s.  s.  White  Dental  Manufacturing  Company 

ar"  applicable  t"  these  crowns 


THE  IIOWLAXD  CROWN. 


63 


base.    The  crown  is  attached  to  the  root  by  a  beaded  Bcrew  |  Fig. 

80)  or  a  screw  with  a  nut,  instead  of  the  Bonwill  pin. 

The  How  Bcrews  and  instruments  [Fig.  81)  are  best  adapted 
for  use  with  these  crowns. 


THE    HOWLAND   CROWN. 

This  crown,  which  is  similar  in  principle  to  one  originally 
introduced  by  Dr.  C.  H.  Mack,  was  devised  by  Dr.  S.  F.  How- 
land.  It  is  attached  like  the  How  dovetail  crown,  with  screws 
that  are  first  inserted  in  the  root.  It  is  used  mostly  on  bicuspid 
and  molar  roots,  and  consists  of  a  hollow  porcelain  crown,  with  a 
cavity  in  the  crown  sufficiently  large  to  admit  the  screw  or  pins, 
and,  when  necessary,  a  small  portion  of  the  root  (Fig.  82). 

The  method  of  setting  this  crown,  as  described  by  Dr.  How- 
land,  is  to  shorten  the  root  even  with  the  gum  with  a  stump  file ; 
fit  the  crown  to  the  root ;  enlarge  the  root-canal  so  that 
a  threaded  pin  of  proper  size  will  pass  in  easily,  par- 
tially fill  the  canal  with  zinc  phosphate,  and  press  the 
pin  to  its  place  with  pliers.  The  crown  should  then  be 
filled  with  zinc  phosphate  and  pressed  to  its  place,  care 
being  taken  to  hold  it  in  position  until  the  cement 
I  sets  (Fig.  83).  If  any  operator  distrusts  the  ability  of 
zinc  phosphate  to  make  a  perfect  joint,  a  small  quan- 
tity   of  silver    amalgam    or 

J  .  .    &       .       Fia.  82. 

gutta-percha  can  be  used  to 

advantage. 

This  crown  is  strong,  and 
during  its  test  of  several 
years  none  have  broken  so 
far  as  known.  The  mode  of 
fastening  is  strong,  and  has 
the  advantage  of  two  pins  when  set  on  a  bicuspid  having 
two  root-canals.     It  is  simple,  and  when  set — no  metal  being  in 


Fig.  81. 


ca 


Fig.  83. 


Fig.  84. 


sight — it  is  a  perfect  imitation  of  the  natural  tooth  (Fig.  84). 

THE    LOGAN,    BROWN,   AND    NEW    RICHMOND   CROWNS. 

These  crowns  have  their  platinum  posts  or  pins  baked  in  the 
body  of  the  porcelain.     In  the  Logan  crown  the  base  is  made 


<34 


ARTIFICIAL  CROWS-  ASD  BRIDGE- WORK. 


concave,  to  facilitate  its  adjustment  to  the  end  of  the  root,  and 
to  give  tlic  cement  a  more  reliable  form.  The  base  of  the  Brown 
crown  is  convex,  and  that  of  the  new  Richmond  V-shaped,  from 
mesial  to  distal  side. 


Pig.  85. 


Fig.  86. 


Fig.  87. 


The  preparation  of  a  root  for  each  of  these  crowns  is,  in 
general,  similar  to  that  for  the  Bonwill  crown.  The  root-canal 
is  enlarged,  and  shaped  so  that  the  post,  if  possible,  at  least  at 
its  point,  will  fit  tightly.  Gutta-percha  or  oxyphosphate  is  used 
for  cementing  in  [(reference  to  amalgam. 
Fig.  89.  Fig.  90.  Fig.  91.       Fig.  92. 


The  Logan   Crown. — The   Logan  crown,  now  so  extensively 
used,  ie  the  invention  of  Dr.   M.   L.  Logan.     The  method  of 

mounting   18  explained  in    all  its   details  in  the    following  article 
by  Dr.  W.  8.  How: 

'•  Kig.  s">  -hows  a  superior  right   central  root,  an  end  appear- 
ance of  tie-  aame,  and  a  Logan  crown,  front  view.     Fig.  86  ex- 


THE  LOGAN  CROWS. 


65 


hibits,  at  a  right  angle  to  the  plane  of  the  first  figure,  the  Bame 
root,  its  end,  and  the  Logan  crown,  side  view.  In  both  figures 
the  root-canal  is  supposed  to  have  been  first  drilled  to  a  gauged 
depth  with  an  engine  twist-drill,  No.  154,  and  then  enlarged 
by  means  of  a  fissure-bur,  No.  70,  to  the  tapering  form  shown  ; 
Fig.  93.  Fig.  94.  Fig.  95.  Fig.  96. 


the  walls  being  subsequently  grooved  with  an  oval  bur,  No.  90. 
The  enlarged  section.  Fig.  87,  shows  the  crown  adjusted  on  the 
root  by  means  of  cement  or  gutta-percha,  which  surrounds  the 
post  and  fills  all  the  spaces  in  the  root  and  crown.  Fig.  88 
shows  the  completed  crown.  Fig.  89  exhibits  a  bifurcated  bicus- 
Fig.  97.  Fig.  98.  Fig.  99.  Fig.  TOO.  Fig  101. 


pid  root,  its  end  appearance,  and  a  Logan  crown  adjusted 
to  the  root.  Fie;.  90  illustrates  the  best  manner  of  bend- 
ing  the  post.  Fig.  91  shows  a  split  post,  and  its  adapta- 
tion to  a  bifurcated  bicuspid  root  is  seen  in  Fig.  92. 

Figs.  93  and  94  exhibit  the  mode  of  mounting  the  Logan  crown 

on  a  superior  molar  root,  and  Figs.  95  and  96  the  same  crown 

in  its  relations  to  an  inferior  molar  root. 

"  The  preceding  figures  clearly  present  to  the  mind's  eye  of  the 

expert  dentist  the  essential  features  of  the  Logan  crown  and  the 

method  of  mounting  it. 

5 


6G 


ARTIFICIAL  CROUX-  AXD  BRIDQE-WORK. 


Fro.  103. 


"The  details  are  as  follows:  111  every  instance  where  a  root 
ia  deemed  ready  to  receive  its  rilling,  it  should  first  be  measured 
through  it-  canal  from  the  cervical  opening  to  the  apical  foramen, 
and  this  may  be  accurately  done  with  a  gauge  adjustable  on  a 
delicate  canal-explorer  (Fig.  97).  The  same  device  serves  to 
measure  the  distance  from  the  apex  to  which  the  canal  should 
then  be  filled  (Fig.  98).  It  also  gauges  the  depth  to  which  the 
drill  may  be  carried.  The  proper  degree  of  enlargement  from  the 
bottom  of  the  drilled  hole  will,  of  course,  depend  on  the  observed 
size  and  character  of  the  root.  Every  dentist  should  familiarize 
himself  with  generic  tooth-forms,  so  that  when  the  length  of  an 
Fig.  102.  incisor,  cuspid,  or  other  tooth- 
*     A     root  is  known,  he  can  so  nearly 

determine  its  hidden  outlines 

as  to  form  with  precision   a 

corresponding  enlargement  of 

the    root-canal,     such    as    is 

shown   by   the    several  cuts. 

For  preparing  the  roots,  the 

Ottolengui  root-reamers  (Fig. 

102)  and  facers  (Fig.  103)  are 
very  desirable  instruments.  The  ream- 
ers are  made  in  three  sizes  to  correspond 
with  the  Logan  pins.  With  a  root- 
reamer  of  the  appropriate  size,  the  root- 
canal  is  enlarged  to  fit  the  pin  along  its 
whole  length,  and  so  hold  the  crown  firmly  independently  of  the 
cement.  With  a  root-facer  a  labial  slope  is  given  to  the  root-end, 
so  that  the  crown  neck  shall  fit  under  the  edge  of  the  gum.  Fig. 
104  shows  the  method  and  its  result,  and  the  cross-section  shows 
how  t } j . -  cemenl  incases  the  pin.  The  suitable  preparation  of 
the  bifurcated  root-  of  some  bicuspids  and  of  all  the  molars 
is  a  matter  involving  difficulties  of  an  unusual  character  and 
requiring  good  judgment.  The  feasibility  of  -putting  the  post 
of  a  Logan  crown  to  adapt  it  to  the  bifurcated  root  of  a  bicuspid 
i-  shown  by  Figs.  91  and  92.  This  example  directs  attention  to 
the  peculiar  shape  of  the  post,  in  which  there  i-  effected  such 
a  distribution  of  tin:  metal  thai  its  greatest  strength  is  in  the 


THE  LOGAN  CROWN. 


>I7 


line  of  the  greatest  stress  that  will  in  use  1»'  brought  to  bear 
on  the  crown,  while  the  least  metal  is  found  at  the  point  of  tin- 
least  strain  :  the  applied  part  of  the  post  being1  in  outline  nearly 
correspondent  to  that  of  the  root  itself.  The  root-canal  is  like- 
wise conformably  enlarged  to  receive  the  largest  and  stiffest  post 
which  the  size  and  shape  of  the  root  will  permit. 

"The  fitting  of  a  Logan  crown  to  a  root  may  be  done  with  a 
wet  stump-wheel  in  the  engine  hand-piece.  A  safe-side  crown 
corundum-wheel  (Fig.  105)  can  be  used  in  the  same  manner. 
It  also  affords  the  greatest  facility  for  the  slight  touehes  required 
to  abrade  the  thin  cervical  borders  of  the  crown,  which  may  by 
this  means  be  done  without  encroachment  on  the  post. 

Fio     104. 


"  By  the  old  method  of  adapting  pivot-teeth  to  roots,  the 
close  fitting  of  the  crown  precluded  the  use  of  a  plastic  packing, 
because  its  thinness  over  the  surface  of  the  joint  made  the  pack- 
ing liable  to  break  loose  under  the  shock  and  strain  of  use. 
The  recess  in  the  Logan  crown  obviates  this  defect  by  providing 
a  receptacle  for  a  considerable  interior  body  of  cement  that  will 
be  deep  enough  to  be  self-sustaining  internally,  and  yet  allow 
the  peripheral  portions  of  the  root  and  crown  to  approach  each 
other  so  closely  that,  though  only  a  film  of  packing  remain,  it 
will  still  be  strong  enough  to  insure  the  persistent  tightness  of 


,;s  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

the  joint.     This  annular  boss  if  form  sd  of  amalgam  also  adds 
strength  in  souk-  cases  to  the  mount. 

"  When  enough  of  the  natural  crown  remains,  it  is  well  to 
leave  standing  some  of  the  palatal  portion,  and  cut  the  root 
under  the  gum  margin  at  only  the  labial  part,  as  shown  by 
Fig.  99.  The  safe-side  crown  wheel  is  especially  useful  in  such 
eases  (Fig.  106).  Thus  the  labial  joining  of  the  root  and  crown 
will  be  concealed,  and  the  other  parts  of  the  joint  will  be  acces- 
sible for  finishing  and  keeping  clean  (Fig.  100).  The  Logan 
crown  may  be  ground  until  a  large  part  shall  have  been  removed 
for  adaptation  to  the  occluding  tooth  or  teeth  without  seriously 
impairing  its  strength  (Fig.  101).  This  crown  also  in  such 
•cases  maintains  the  translucency  which  is  one  of  its  peculiar  ex- 

Fio.  105.  Fig.  106. 


■cellences,  owing  to  its  solid  porcelain  body,  and  the  absence  of 
a  metallic  backing  or  an  interior  largely  filled  with  cement  or 
amalgam. 

"  The  distal  buccal  root  of  the  natural  superior  molar  is  nearly 
always  too  small  to  receive  a  post  of  any  useful  diameter,  and 
therefore  the  Logan  superior  molar  crown  has  but  two  posts, 
which  like  those  of  the  inferior  molar  crown  are  square,  and 
thus  may  be  easily  barbed,  as  may  also  the  ribbed  posts  of  the 
crowns  lor  the  anterior  tooth-roots.  These  posts  are  huge  enough 
in  ;dl  the  Logan  crowns  to  answer  in  any  given  case,  and  can  of 
course  be  easily  reduced  to  suit  thin  or  short  roots. 

"  Any  of  the  cements  or  amalgams  may  be  used  in  fixing  these 
crow  ns,  bul  good  gutta-percha,  softened  at  a  low  heat  and  quickly 
wrapped  around  the  beated  crown-post,  which  is  nt  once  seated 


THE  BRO  WX  CRO  WN. 


69 


in  the  root,  forms  the  best  mounting  medium,  and  has  the  gnat 
advantage  of  permitting  a  readjustment,  or,  if  need  be,  the  ready 
removal  of  the  crown  by  grasping  it  with  a  pair  of  hot  pliers  or 
forceps,  and  holding  it  until  the  gutta-percha  is  sufficiently 
softened." 

The  Brown  Crown. — Fig.  107  is  a  lateral  view  of  a  porcelain 
crown,  with  an  iridio-platinum  pin  baked  in  position,  invented  by 
Dr.  E.  Parmlv  Brown.  The  pin  has  great  strength  at  the  neek 
of  the  tooth,  where  the  strain  is  heaviest,  and  this  strength  is  fur- 
ther increased  by  extending  the  porcelain  up  on  to  the  pin. 

Fig.  108  is  a  front  view  of  the  same  crown,  showing  by  the 
dotted  lines  the  shape  of  the  pin  and  the  position  which  it  occu- 
pies in  the  crown. 

The  pin  is  flattened  laterally,  affording  a  strong  hold  in  the 
porcelain  without  bringing  the  pin  too  near  the  surface  in  thin 


Fig.  10"! 


Fig.  108. 


Fig.  109. 


Fig.  110. 


teeth,  while  it  also  permits  alteration  of  the  palatal  surface  of 
the  crown  in  a  close  "  bite "  without  risk  of  weakening  the 
body. 

Fig.  109  is  a  view  of  the  bicuspid  crown,  in  which  a  pin  is 
provided  for  each  root  of  two-rooted  bicuspids. 

Fig.  110  is  a  view  of  a  bicuspid  crown  with  the  two  pins 
pressed  together,  forming  a  single  pin  of  great  strength  for  a 
tooth  with  only  one  root. 

The  double  pin  in  the  bicuspids  prevents  the  gradual  loosen- 
ing of  the  crown  by  the  rotary  movement  of  the  jaws  in  mastica- 
tion, which,  acting  on  the  two  cusps,  exerts  such  leverage  as  to 
sometimes  turn  and  break  down  ordinary  crowns  where  only  one 
pin  is  used. 

The  roots  are  ground  concave  to  fit  the  crowns  with  corundum- 
points  or  a  Willard  countersink  bur,  and  close  joints  are  made 


70 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


well  under  the  gum,  the  pins  being  set  with  oxyphosphate 
cement.  The  canal  should  he  enlarged  enough  only  to  admit 
the  pin,  which  should  tit  snugly  throughout  its  entire  length,  the 
better  to  distribute  the  leverage  exerted  by  the  crown,  and  thus 
directly  to  increase  the  strength  of  the  attachment.  (For  process 
of  cementation,  see  article  on  "Insertion  and  Cementation.") 

Thx  X<  w  Richmond  Grown. — To  illustrate  and  describe  the 
method  of  mounting  this  crown,  a  superior  left  central  incisor 
root  will  serve  as  a  typical  case,  and  its  projecting  end  is  to  be 
shaped  as  seen  in  Figs.  Ill  and  112.  This  can  be  rapidly  done 
with  a  narrow  safe-sided  Hat  or  square  file,  the  angles  of  the 
slopes  being  such  that  the  gum  on  the  labial  and  palatal  aspects 
will  not  interfere  with  nor  be  disturbed  by  this  preliminary  work, 
as  the  root  end  is  not,  in  this  operation,  to  be  cut  quite  down  to 


Fig.   111. 


Fig.  112. 


Fjg.  113. 


the  gum.  Aii  Ottolengui  root-reamer  No.  2  is  then  employed  to 
bore  out  the  root  to  receive  the  crown-post,  which  is  of  (lie  same 
size  and  shape  as  the  Logan  crown-post  for  a  central  incisor. 

The  Bectional  view  (Fig.  113)  shows  the  relation  of  the  reamer 
t..  the  n.ot.  The  new  Richmond  crown  (Fig.  114)  is  then  tried 
on  the  root  (Fig.  115),  and  its  position  relative  to  the  adjacent 
and  occluding  teeth  noted.  If  the  cutting-edge  of  the  crown  is 
to  he  broughl  out  for  alignmenl  with  its  neighbors,  the  root  can 
!„•  drilled  ;i  little  deeper,  and  the  reamer  pressed  outward  as  it 
revolvee  to  cut  the  labial  wall  of  the  cavity.  The  palatal  root- 
slope  must  then  be  filed  to  make  the  V  correspond  to  the  changed 

inclination  of  the  crown. 

Thus,  by  alternate  trial  and  reaming  and  fling,  the  crown 
may  he  fitted    to  the  root    and   adjusted    in  its  relation-  until    the 


THE  XEW  RICH  MO  XD  CROWX. 


71 


post  has  a  close,  solid  bearing  against  the  labial  and  palatal  walls 
of  the  enlarged  pulp-chamber,  and  the  crown-slopes  arc  separated 

from  the  root-slopes  by  the  thickness  of  a  sheet  of  heavy  writing- 
paper.  This  space  can  be  accurately  gauged,  and  the  root-slopes 
conformed  to  the  crown-slopes  by  warming  the  crown  and  put- 
ting on  its  slopes  a  little  gutta-percha,  so  that  an  impression  of 
the  root-end  may  be  taken,  and  the  root-slopes  dressed  with  a 
file  until  the  film  of  gutta-percha  proves  to  be  of  equal  thinness 
on  both  slopes. 


Fig.  114. 


Fig    115. 


Fig    118. 


Fm.  117. 


To  permanently  attach  the  crown.  Dr.  Richmond  usually  takes 
a  thin,  perforated  disk  of  gutta-percha,  pushes  the  post  through 
it,  warms  the  crown,  presses  it  into  place,  and  when  cooled 
removes  it,  and  with  a  sharp  knife  trims  away  the  gutta- 
percha close  to  the  crown-neck.  He  then  warms  the  crown, 
puts  a  very  little  oxyphosphate  cement  on  the  post,  and  presses 
the  crown  home.     Fig.  116  shows  the  completed  crown. 

The  obvious  advantages  of  the  device  are  the  readiness  with 
which  the  slopes  of  the  root-end  may  be  shaped  with  a  file;  the 
facility  with  which  these  slopes  may  be  given  any  angle  to  set 
the  crown  out  or  in  at  the  base  or  at  the  cuttin^-ed^e,  or  to  give 
it  a  twist  on  its  axis;  the  certainty  that,  once  adjusted,  the  final 
setting  will  exactly  reproduce  the  adjustment;  the  assurance 
that  in  use  the  crown  will  not  be  turned  on  its  axis, — a  most 
common  cause  of  the  loosening  of  artificial  crowns;  the  firm- 
ness of  its  resistance  to  outward  thrust  in  the  act  of  biting. 
This  is  made  apparent  by  Fig.  117,  wherein  it  will  be  seen 
that  in  an  outward  movement  the  crown  B  would  rock  upon  A 
as  a  pivot.  The  dotted  line  D  shows  how  the  crown-slope  is 
resisted  by  the  root-slope,  which  extends   so  far  towards  the 


72 


ARTIFICIAL  CROWN-  AND  BRIDOE-WORK. 


incisive  edge  that  a  much  firmer  support  is  given  to  the  crown 
than  if  the  resistance  should  be,  as  it  usually  is,  on  the  line  of 
the  gingival  margin  C. 

For  roots  that  have  become  wasted  below  the  gum-surface  it 
is  not  suitable,  except  in  such  cases  as  are  decayed  under  the 
labial  or  palatal  gum-margin  only,  but  have  yet  projecting  the 
approximal  portions  of  the  crown  (Fig.  118). 


Fig.   118. 


Fig.  119. 


Fig.  120. 


The  sectional  view  (Fig.  119)  and  the  perspective  plan  views 
(Fig.  120)  illustrate  the  manner  of  mounting  these  crowns  on 
this  class  of  roots.     The  finished  crown  appears  as  in  Fig.  120. 

The  cases  for  which  this  crown  seems  specially  adapted  are 
such  as  have  some  considerable  portion  of  the  natural  crown 
remaining. 


REMARKS    ON     THE    USE    OF     PORCELAIN    CROWNS. 

Porcelain  crowns  have  some  decided  advantages.  They  are 
especially  useful  in  many  cases  where  an  inexpensive  or  easily 
adjusted  crown  is  required;  or  where  some  pathological  con- 
dition limits  the  probable  durability,  or  permanency,  of  any 
operation.  In  the  insertion  of  porcelain  crowns,  the  removal  of 
the  whole  or  a  part  of  the  natural  crown,  which  could  be  uti- 
lized to  some  extent  as  a  foundation  by  other  systems,  has  given 
rise  to  various  objections.  If  the  natural  crown  is  entirely  cut 
away,  the  pin,  or  post,  upon  which  almost  the  entire  support  of 
the  artificial  crown  is  tin-own,  acts  like  a  lever  in  (be  root-canal, 
there  being  no  band  or  brace  to  relieve  the  strain.  With  the 
whole  force  of  mastication  bearing  directly  upon  these  pulpless 
root-,  whose  disintegration  is  slowly  bu1  constantly  progressing, 


REMARKS  ON  THE  USE  OF  PORCELAIN  CROWNS.  73 

the  inevitable  result  can  well  be  conjectured.  Sooner  or  later 
they  are  fractured,  and  their  usefulness  as  a  foundation  ended. 
Then,  again,  if  porcelain  crowns  are  attached  with  amalgam, 
the  discoloration  of  the  line  of  union  with  the  root,  if  subse- 
quently exposed,  is  disfiguring.  These  facts,  and  the  lack  of 
strength  incident  to  some  forms  of  construction,  are  the  princi- 
pal objections  urged  against  porcelain  crowns  as  ordinarily 
inserted. 


CHAPTEE  II. 


PORCELAIN  CROWN  WITH  GOLD  COLLAR  ATTACHMENT. 

A  (iOLD  collar,  either  seamless  or  soldered,  can  be  used  advan- 
tageously in  combination  with  many  of  the  porcelain  crowns. 

The  root  having  been  properly  prepared,  a  collar  is  adjusted 
and  adapted  to  it  the  same  as  for  a  gold  collar  crown  (see  page 
84).  The  porcelain  crown,  the  base  of  which  should  be  fully 
as  large  as  the  end  of  the  root,  is  then  ground  even  with  the 
cervical  walls,  and  fitted  into  the  collar,  which  should  be  trimmed 
and  burnished  to  the  form  of  the  crown.  Dr.  Townsend's  fusi- 
ble  metal  die,  used  in  the  following  manner,  facilitates  the  appli- 
cation of  a  collar  to  a  Logan  crown  (Fig.  121).  Enlarge  the 
Fig.  121.  root-canal  to  receive  the  Logan  pin.  Grind  a 
f\  Logan  crown  to  fit,  and  articulate  it.     Construct 

a  band  of  ISTo.  30  gold  (or  of  No.  32  crown-metal, 
which  is  better)  wide  enough  to  project  beyond 
the  end  of  the  root  say  -fa  of  an  inch.  Cut  a 
wooden  peg  about  an  inch  long 
and  taper  one  end  of  it  to  the 
general  size  and  shape  of  the 
pin  in  the  Logan  crown.  Place 
the  band  on  the  root,  insert  the 
peg  in  the  canal,  and  fill  up  the 
band  with  Melotte's  moldine  or 
with  stiff'  putty,  pressing  it  closely  about  the  peg. 
Remove  all  together  and,  holding  the  die  over  the 
flame  df  an  alcohol  lamp  to  melt  the  fusible  metal, 
place  them — the  band,  peg,  and  moldine,  in  the 
same  relative  positions  they  occupied  in  the  root 
— on  the  die,  with  the  pin  in  the  socket,  and  press  down  until 
the   moldine  rests  on  the  surface  of  the  molten   fusible  metal. 


■  li-t     t,  Fusible  Metal. 


PORCELAIN  CROWN   WITH  GOLD  COLLAR  ATTACHMENT.     75 


Chill;  in  cooling,  the  fusible  metal  takes  a  firm  hold  on  the 
lower  edge  of  the  gold  band,  holding  it  Becurely  in  place  during 
the  remainder  of  the  operation.  Remove  the  peg  and  the 
moldine,  and  with  a  wooden  mallet  drive  the  Logan  crown  into 
the  band  until  the  porcelain  rests  upon  the  fusible  metal.  Burnish 
the  band  smoothly  about  the  crown.  When  the  gold  is  perfectly 
adjusted  to  the  porcelain,  melt  the  fusible  metal  to  release  the 
band  and  crown. 

If  the  work  has  been  carefully  done,  the  crown  with  its  band 
will  then  be  read)'  to  be  set,  as  the  articulation  and  lit  will  not 
have  been  disturbed. 

Enough  of  the  collar  should  be  trimmed  away  at  the  labial  por- 
tion to  prevent  too  conspicuous  exposure  of  the  gold  (Fig.  122). 

Fio.  122.        Fig.  123.  Fig.  124.         Fig.  125.         Fig.   126.         Fig.  127. 


This  collar  combination  is  available  in  very  difficult  cases,  as, 
for  instance,  when  a  root  is  decayed  upon  one  side  far  beneath 
the  gum,  as  seen  in  Fig.  123. 

Such  an  operation,  when  completed,  would  appear  in  vertical 
section  like  Fig.  124,  and  a  view  in  perspective  would  resemble 
Fig.  125.  The  collar  is  also  very  useful  wherever  the  root  and 
crown  are  not  made  flush  and  smooth  at  every  point,  as,  if  prac- 
ticable, they  should  always  be. 

Dr.  E.  C.  Kirk,  of  Philadelphia,  uses  for  bicuspids  and  molars 
a  Foster  crown  in  combination  with  a  collar  (Fig.  126).  A  collar 
is  made,  and,  on  being  fitted  to  the  root,  is  cut  narrow  on  the 
labial  side,  and  left  wide  on  the  lingual,  so  that  it  shall  extend 
nearly  to  the  cusp  of  the  crown  when  finished  (Fig.  127).  (The 
seamless  gold  collars  are  well  suited  for  application  to  this  style 
of  crown.) 


76  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

The  crown  selected  should  have  a  somewhat  greater  circum- 
ference at  the  base  than  the  collar,  so  that  when  ground  down 
somewhat  conically  on  its  lingual  and  approximal  surfaces,  it 
can  be  tightly  adjusted  to  the  collar.  If  a  crown  smaller  than 
the  collar  is  used,  a  tight  joint  cannot  be  made.  The  screw  is 
fitted  so  that  it  shall  hold  the  crown  in  proper  relations  with  the 
root.  The  screw  and  crown  are  then  removed,  the  parts  dried,, 
and  the  root-canal  filled  with  a  slow-setting  oxyphosphate  cement,, 
mixed  thin.  The  crown  is  then  pressed  into  its  position,  the 
surplus  cement  flowing  through  the  opening  in  the  porcelain 
and  filling  up  any  interstices  around  or  between  the  band,  the 
root,  and  the  crown.  The  screw  is  then  driven  into  position,, 
and  when  the  cement  is  set  perfectly  hard  the  head  of  th& 
screw  or  the  nut  on  it  is  notched  to  form  a  retaining-pit,  and 
the  countersink  of  the  crown  filled  with  gold. 

Dr.  C.  S.  W.  Baldwin,  o££fifi£S£idk,  caps  the  root  and 
attaches  a  Logan  crown  in  the  following  manner : 

First,  the  root  is  shaped,  the  outer  margin  being  beveled 
about  the  thickness  of  the  gold  used,  to  afford  regular  sides  for 
close  adaptation  of  the  caps.  Then  an  impression  is  taken  and 
a  die  made  in  the  gold  seamless  cap  method.  To  strike  up  the 
cap,  place  No.  32  gauge  gold  plate  on  a  cushion  of  lead,  holding 
the  die  firmly  on  the  gold  where  you  wish  to  produce  the  cap, 
and  strike  until  the  required  depth  is  secured  before  removing  it. 
This  drives  the  gold  and  die  into  the  lead,  forming  a  female  die 
and  a  perfect-fitting  cap  at  once,  in  less  time  than  is  occupied  in 
describing  the  process.  Trim  the  edges  to  fit  the  festoon  of 
tli^  gum,  and  drill  a  hole  from  the  inner  side  for  the  pin,  leav- 
ing the  ragged  n  ess  made  by  drilling  to  catch  in  the  cement. 
Place  tli<'  cap  on  the  root  and  fit  the  porcelain  crown  accurately 
to  it  in  the  desired  occlusion  and  position.  A  Logan  crown 
<aii,  with  little  grinding,  he  made  to  do  good  service  (Fig.  128). 
A  crown  having  the  H-shaped  pin,  but  square  on  the  edge,  like 
Some  of  the  early  patterns  of  Logan  or  Bonwill  crowns,  would 
reduce  the  time  ,,f  setting  and  give  best  results.  Having 
polished  the  edges  of  the  cap,  the  crown  may  lie  conveniently 
adjusted  as  follows:  Place  oxyphosphate  cement  in  the  counter- 
sunk   portion   of  the   porcelain,    and   in   the  canal    only  enough 


PORCELAIN  CROWN   WITH  GOLD  COLLAR  ATTACHMENT.     77 


■cement,  of  creamy  consistence,  to  fill  it,  as  the  pressure  required 
to  force  out  the  surplus  under  the  edges  of  the  cap  destroys 

manv  nicely  adjusted  crowns,  leaving  bulging  irritants  instead 
of  smooth  supports.  If  proper  attention  has  been  given  to 
fitting  crown  and  root,  all  will  come  nicely  to  place,  but  in  some 
cases  of  difficult  adjustment  it  may  be  necessary  to  cement  the 
•crown  to  the  cap  before  fastening  the  pin  in  the  root  (Fig.  129). 


Fn   128. 


Fig.  120. 


Fig.  130. 


Fig.  131. 


In  most  cases  the  gold  band  will  be  invisible  and  below  the 
free  margin  of  the  gum.  Cases  may  occur  where  the  anterior 
teeth  are  prominent,  and  it  will  be  necessary  to  cut  away  the 
top  of  the  cap  in  front,  allowing  the  porcelain  to  come  directly 
in  contact  with  the  root,  the  band  going  deeper  than  in  ordi- 
nary cases,  which  prevents  the  appearance  of  gold  (Fig.  130). 

Dr.  Bonwill's  plan  is  to  cap  the  tooth  with  a  platinum  or  gold 
cap  having  a  slot,  into  which  the  pin  passes  as  it  is  slipped  on 
the  root  (Fig.  131).  The  crown  is  then  fasteued  on  with  amal- 
gam in  the  usual  manner. 


CHAPTER   III. 


THE  WESTON  CROWN. 

Dr.  Henry  Weston's  method  of  crowning  is  described  by 
him  as  follows : 

"  This  crown  represents  on  its  labial  surface  the  ordinary  plate 
tooth,  the  lingual  or  palatal  surface  being  concaved  in  such  a 
manner  as  to  afford  the  largest  amount  of  working  room  with- 
out impairing  its  strength  at  any  point.  The  pins  are  so  im- 
bedded in  the  thickest  part  of  the  crown  that  it  is  not  liable  to 
be  weakened  by  grinding.     Fig.  132  represents  the  crown. 


Fig.  132. 


Fig.  133. 


Fig.  134. 


Fio.  135. 


Fig.  130.        Fig.  137. 


"The  pin  is  made  of  hard  platinum  and  indium,  and  is  spear- 
shaped  and  notched  on  both  edges  to  give  firmness  to  its  anchor- 
age. The  backing  is  of  the  same  metal  and  strongly  soldered 
to  the  pin.     Fig.  133  represents  the  pin. 

"The  preparation  of  the  root  for  the  reception  of  the  crown 
consists  in  the  removal  of  that  part  of  the  tooth  which  is  I"  be 
replace.!  by  the  porcelain.      Fig.  134  shows  the  root  at  this  stage. 

"The  canal  must  be  sufficiently  enlarged  to  allow  space  for 
packing  lt * » 1  *  1  or  amalgam  securely  about  the  pin,  and  the  sides 
reamed  (Fig.  135). 

"The  grinding  of  the  crown  to  the  root  requires  but  little 
labor,  and  the  fitting  may  be  done  directly  on  the  natural  root, 
or  on  a  casl  taken  alter  the  root  has  been  prepared.     This  musl 

78 


THE   WESTON  CRO  WN.  79 

always  be  done  with  the  utmost  neatness  and  precision.  When 
fitting,  the  crown  can  be  held  in  position  by  a  cone  of  wax  in- 
serted in  the  root.  Next  comes  the  adjustment  of  the  pin  to  the 
root  of  the  crown.  After  punching  holes  in  the  backing  to 
receive  the  pins  of  the  porcelain  crown,  bend  the  pin  with  small 
flat-nosed  pliers,  so  that  when  in  its  proper  position  there  shall 
be  a  uniform  space  around  its  entire  surface. 

"Secure  the  tooth  and  pin  together  with  a  cement  of  resin 
and  wax,  invest  in  plaster  and  sand,  and  solder  with  fine  gold 
solder. 

"  It  has  been  my  practice  of  late  years  when  preparing  the 
root  to  leave  just  a  line  of  enamel  around  its  entire  circumfer- 
ence, thus  securing  a  joint  clear  of  the  free  edge  of  the  gum, 
especially  when  gold  is  used.  If  gold  is  to  be  used  as  the 
attachment,  the  rubber-dam  is  indispensable.  When  amalgam 
or  cement  is  used,  the  rubber-dam  may  be  dispensed  with  by 
those  who  prefer  other  methods  of  keeping  out  moisture.  AVhen 
gold  is  to  be  used,  the  root  having  been  previously  properly 
treated,  and  everything  in  readiness  and  the  rubber-dam  in  place, 
put  upon  the  point  of  the  pin  a  pellet  of  phosphate  or  oxychlo- 
ride  of  zinc,  the  size  of  a  No.  7  or  No.  8  excavating  bur  ;  now 
press  the  pin  and  crown  carefully  to  their  exact  position  into 
and  upon  the  root,  and  with  a  delicate  but  blunt-pointed  instru- 
ment, thin  enough  to  reach  the  end  of  the  canal,  pack  the  cement 
firmly  about  the  pin.  The  object  in  using  the  cement  is  to 
secure  the  pin  in  its  place  during  the  first  introduction  of  the 
gold.  By  using  the  hot-air  syringe,  the  cement  will  harden  in 
two  minutes.  Close  the  opening  of  the  canal  about  the  pin  with 
a  rope  of  bibulous  paper,  and  attach  the  crown  to  the  root  and 
adjoining  teeth  on  either  side  with  soft  wax;  see  that  the  joints 
are  exact  in  every  particular,  as  after  the  next  step  mistakes  are 
not  easily  remedied. 

"  Paint  the  joint  from  the  labial  side  with  cement  mixed  to 
the  consistence  of  cream.  Cover  the  labial  surfaces  extending 
over  the  cutting-edges  of  the  porcelain  crown  and  adjoining 
teeth  to  the  thickness  of  three-eighths  of  an  inch  with  carefully 
mixed  impression  plaster.  When  hardened,  the  plaster  may  be 
cut  from  the  cutting-edge  of  the  crown,  and  the  wax  and  the 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

paper  removed.  Now  paint  the  palatal  sides  of  the  joint  with 
the  cement  mixed  to  a  cream-like  consistence,  applied  with  flat- 
tened root-canal  plnggers.  Harden  with  hot  air,  and  the  case  is 
ready  tor  the  gold. 

••  When  filled  and  finished,  the  exposed  dentine  and  enamel 
are  all  covered  with  cohesive  gold  and  porcelain  ;  the  result  will 
be  a  fac-simile  of  Figs.  136  and  137. 

"  If  preferred,  the  cement  in  the  labial  joint  may  be  dispensed 
with,  and  the  space  between  the  crown  and  the  root  carefully 
filled  with  gold  after  the  removal  of  the  plaster,  covering  all  of 
the  exposed  root  and  showing  only  a  fine  line  of  gold  at  the 
margin  of  the  gum. 

••  Where  amalgam  is  used  exclusively  for  the  attachment,  the 
greatest  accuracy  should  be  observed  in  the  proper  articulation 
of  the  crown  before  introducing  or  packing  it  and  in  removing 
carefully  all  excess,  and  the  patient  should  be  cautioned  against 
biting  on  the  crown  until  the  following  day." 


CHAPTEE  IV 


Fig.  138. 


PORCELAIN  CROWNS   WITH  RUBBER  OR  VULCANITE 
ATTACHMENT. 

Fig.  138  illustrates  the  formation  of  such  a  crown.  The  root, 
when  prepared,  extends  at  the  palatal  side  a  little  below  the  line 
of  the  gum  (A)  at  the  point  B.  A  plate  tooth 
(C)  is  ground  and  fitted  to  the  root.  An  iridio- 
platinum  post  is  then  fitted  to  the  root,  flattened 
slightly  and  bent  at  D,  and  riveted  to  the  tooth. 
The  proper  alignments  of  the  tooth  and  post  to 
the  root  are  then  obtained,  and  they  are  iu  vested 
and  the  post  soldered  and  strengthened  at  the 
point  D.  The  backing  is  then  grooved  and 
notched  slightly,  wax  applied,  the  crown  ad- 
justed to  the  root,  and  the  wax  shaped  so  as  to  a\ 
form  a  foundation  and  overlapping  edge  at  the 
palatal  portion  (E).  The  crown  is  then  re- 
moved, invested  in  a  flask,  packed  with  rubber, 
and  vulcanized.  In  trimming  and  finishing, 
the  rubber  is  allowed  to  form  a  partial  band  or 
collar  around  the  palatal  portion  of  the  root, 
where  it  will  not  show.  It  is  then  cemented  on  to  the  root  with 
oxyphosphate. 

The  "Weston  crown  and  the  four-pin  How  crowns  have  advan- 
tages over  ordinary  plate  teeth  in  the  construction  of  this  style 
of  work. 


81 


THE  GOLD   SYSTEM. 


CHAPTEE  V. 


PORCELAIN  AND  GOLD  CROWN  WITHOUT  A  COLLAR. 

The  root  of  a  cuspid  will  be  taken  as  a  typical  case  to  illustrate 
the  construction  of  this  style  of  crown. 

The  end  of  the  root  is  prepared  the  same  as  for  a  porcelain 
crown  (Fig.  139).  The  root-canal  is  then  uniformly  enlarged  a 
reasonable  distance  up,  with  a  drill  which  will  tightly  fit  the 
opening.     Into  the  canal,  gauging  its  full  diameter,  is  fitted  a 


Fig.  139. 


Fig.  140. 


Fig.  141. 


Fig.  142. 


Fig.  143. 


piece  of  iridio-platinum  wire,  tapered  oil'  to  a  point,  so  that  by 
introducing  it  far  up  the  canal  greater  strength  can  be  obtained, 
and  the  root  rendered  less  liable  to  longitudinal  fracture  from 
pressure  in  a  forward  direction.  A  piece  of  platinum  plate,  a 
trifle  larger  than  the  end  of  the  root,  of  about  No.  30  U.  S. 
standard  gauge,  with  a  hole  punched  in  its  enter,  is  then  slipped 
<>n  the  post,  which  it  musl  lit   tightly  (Fig.  140). 

When    the   post  is  adjusted    firmly  in    the  canal,  the  platinum 
plate  i-  pressed  down  on  the  root,  and  burnished  into  the  orifice 
82 


PORCELAIN  AND  GOLD  CROWN  WITHOUT  A   COLLAR.        83 

of  the  canal  around  the  post.  When  the  post  is  withdrawn  from 
the  root,  the  platinum  will  adhere  to  it,  if  fitted  closely,  with- 
out the  use  of  wax.  A  particle  of  pure  gold  with  borax  is  put 
in  the  joint,  and  melted  in  the  flame  of  an  alcohol  lamp.  Barely 
enough  gold  should  be  used  to  unite  the  parts.  When  soldered, 
the  post  and  cap  are  again  adjusted  in  the  mouth  and  the  cap 
nialleted  and  burnished  to  the  form  of  the  end  of  the  root,  so 
that  its  edge  will  leave  a  mark  on  the  platinum.  The  cap,  on 
being  removed,  should  be  trimmed  to  this  mark,  and  again  bur- 
nished on  the  root  (Fig.  141).  Sometimes  around  the  palatal 
portion  of  the  root  the  platinum  may  be  slightly  burnished  over 
the  edge.  The  post  is  then  cut  off'  just  above  the  platinum,  and 
a  plate  tooth  fitted,  backed,  and  cemented  with  wax  in  position 
on  the  cap.  The  whole  is  then  removed,  invested,  and  soldered 
with  gold  at  least  twenty  carats  fine,  which  should  be  melted  in 
at  the  base  of  the  post,  as  at  this  point,  when  in  use,  the  strain 
is  very  great.  The  post  is  then  barbed,  and  the  crown  is 
cemented  to  the  root  with  gutta-percha  or  oxyphosphate  cement 
(Fig.  142). 

Dr.  F.  T.  Van  Woert,  of  Brooklyn,  K  Y.,  in  constructing 
crowns  uf  t li ill  iiUIl,  shapes  the  end  of  the  root,  and  adapts  the 
cap  as  shown  in  Fig.  143.  The  slant  given  to  the  palatal  side 
aids  the  root  to  resist  force  in  a  forward  direction. 


/ 


CHAPTER  VI. 

GOLD   COLLAR   CROWNS. 


This  style  of  gold  crown  includes  those  methods  which  consist 
in  banding,  capping,  and  hermetically  inclosing  with  gold  the 
end  or  the  neck  of  a  root,  with  or  without  any  portion  of  a 
natural  crown,  for  the  purpose  of  securing  stability  to  the  arti- 
ficial crown,  preventing  fracture  of  the  root  and  decay  of  the 
parts,  thus  permanently  preserving  them.  This  method  pos- 
sesses much  practical  value  as  a  preserver  of  tooth-structure  and 
restorer  of  usefulness  to  the  teeth,  and  affords  excellent  supports 
for  bridge-work. 

Thr-"iw •  nf  thr  nnllir  rrniin  hVi-ftiwn^nnlfncnhpd  by  Dr.  Wm, 
H.  Dwindle  in  the  application  of  the  method  to  a  crown  with  a 
porcelain  front,1  and  by  Drs.  AV.  1ST.  Morrison2  and  J.  B.  Beers3 
in  the  construction  of  all-gold  cap  crowns,  fyy 

Collar  crowns  of  which  the  part  that  essentially  constitutes 
the  cap  is  constructed  in  sections,  will  be  first  described. 

THE    CONSTRUCTION    AND    ADAPTATION    OF   COLLARS. 

Careful  study  of  the  different  forms  of  crowns  and  roots,  and 
of  the  anatomical  structure  and  relationship  of  the  contiguous 
parts,  is  most  essential  for  the  perfect  construction  and  adapta- 
tion of  collars,  bands,  or  ferrules,  as  they  arc  variously  designated. 

Many  devices  and  methods  in  use  facilitate  this  operation, 
but  its  skillful  performance  can  only  be  attained  by  study  and 
practice,  a--  is  proved  by  the  easy  and  perfect  manner  in  which 
it  i>  done  by  experts  in  crown-  and  bridge-work,  who  use  no 
appliances  hut  pliers  and  shears  guided  by  an  intuitive  percep- 
tion of  the  requirements  of  each  case. 

1  American  .Journal  of  Dental  Science,  April,  1856. 

Missouri  Dental  Journal,  M.iy,  1869. 
s Circular  to  dental  profession,  1878. 

84    /J\  /S*3£ 


THE   CONSTRUCTION  AND  ADAPTATION  OF  COLLARS.        85 


Fio.  144. 


The  collar  is  preferably  made  of  coin  gold,  or  of  22  to  23-carat 
gold  plate.  Pure  gold  plate  lined  with  platinum  is  also  used, 
and  iridio-platinum  plate  in  special  cases. 

Gold  plate  of  No.  3^  to  Xo.  3£  or  gold  and  platinum  or 
iridio-platinum  of  No.  34  or  No.  35,  IT.  S.  standard  gauge, 
affords  the  requisite  strength,  together  with  easy  adaptation  to 
the  form  of  the  crown  or  root.  The  natural  crown  or  root 
having  previously  been  properly  prepared  (see  page  39),  a  strip 
of  the  metal  is  cut  of  the  length  required,  and  generally  from 
one-fourth  to  one-half  of  an  inch  in  width  (Fig.  144).  The  end 
to  form  the  underlap  is  beveled  with  a  file.  The  strip  is  then 
bent  with  suitable  pliers  (Fig.  145)  to  the  average  lorm  (Fig.  146), 
any  special  deviation  from  such  average 
being  noted  (Fig.  147),  and  to  the  size  of  the 
cervical  periphery  of  the  root  of  the  tooth 
to  be  crowned.  It  is  then  placed  on  the 
root  and  adapted  as  closely  as  possible  to 
its  form,  with  the  upper  edge  of  the  metal 
pressing  gently  under  the  free  edge  of  any 
portion  of  the  gum  it  may  meet.  It  is  then 
removed  and  cut  so  as  to  allow  the  ends 
to  lap  over  slightly.  The  adaptation  to 
the  root  is  then  continued,  during  which 
process  the  metal  should  be  heated  and 
ehilled  in  water  after  each  trial,  in  order 
to  maintain  the  shape  given  to  it.  At  the 
last  adjustment  to  the  root,  the  lap-over  is 
marked  on  the  metal  with  a  sharp-pointed 
instrument.  The  joint  is  made  at  this 
mark  by  placing  there  the  least  possible 
quantity  of  solder  and  holding  the  collar  in  the  flame  of  an  alco- 
hol lamp  or  a  blue  gas  flame.  The  collar  is  then  slipped  on  the 
point  of  a  small  anvil,  and  the  joint  tapped  down  and  trimmed 
leve 


Fig.  145. 


hen  a  mandrel  is  used  in  forming  a  collar,  the  size  or 
shape  is  first  taken  by  encircling  the  root  with  a  piece  of  fine 
iron  or  copper  wire,  about  Xo.  28  IT.  S.  standard  gauge,  and 
twisting  the  ends  together  on  the  labial  side.     The  wire  is  then 


86 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  146. 


0.00. 


to 


a 


pressed  up  on  the  root  about  as  far  as  the  upper  edge  of  the 
collar  is  to  go,  and  burnished  to  the  sides  (Figs.  148  and  149). 
The  wire  ring  is  then  carefully  removed,  laid  on  a  piece  of  air- 
chamber  tin,  a  piece  of  flat 
iron  put  over  it,  and  with 
a  blow  from  a  hammer  on 
the  iron  the  wire  is  driven 
into  the  tin  (Fig.  150).  The 
wire  ring  is  removed  from 
the  tin,  slipped  on  a  man- 
0_Jj  (       J       drel1   that  represents  the 

form  of  the  root  to  be 
crowned  and  pressed  down 
gently  as  far  as  it  will  go 
without  stretching  the  wire 
(A,  Fig.  151).  The  dis- 
tance from  the  end  of  the 
mandrel  to  the  wire  is  then 
measured  and  marked  on 
a  strip  of  paper,  and  the 
wire  removed.  The  gold 
to  form  the  collar  is  then 
bent  and  shaped  on  the 
mandrel,  with  the  edge 
which  is  to  form  the  cer- 
vical portion  (B)  placed  a 
little  below  the  line  of  tlie 
wire  (A),  as  shown  by  the 
measurement  previously 
taken.  The  ends  of  the 
gold  are  beveled,  slightly 
lapped,  and  the  edge  of  the 
lap-over  marked  (C).  Tlie 
collar  is  then  removed  from  the  mandrel  and,  the  ends  being 
held  together  with  common  tweezers,  which  are  grasped  by 
pliers,  <>r  better  still,  by  a  small  hand-vise  (Pig.  152),  tlie  extreme 

•A  description   of  mandrels  will   bo  found  in   the  chapter  on  the  "Mandrel 
System." 


G 


The  palatal  side  of  the  HUperior  molars,  in  many  cases, 
is  of  tlie  lari^e  oval  form  Indicated  by  tlie  outer  line  to  the 
form  of  the  first  molar.  The  small  spurs  indicate  the 
point!  generally  found  tlie  most  suitable  to  make  the  joi tit. 


' 


THE  CONSTRUCTION  AXD  ADAPTATION  OF  COLLARS. 


87 


, 


outer  end  of  the  joint  is  united  by  an  atom  of  soWer  with  a 
blow-pipe.  The  points  of  the  tweezers  prevent  the  solder  from 
flowing  along  the  joint,  the  cervical  portion  of  which  is  left  open 
Fig.  147.  Fig.  148.  Fig.  149.  Fig.  150. 


for  the  present.  The  collar  is  then  shaped  to  the  form  given  by 
the  wire  in  the  tin,  after  which  it  is  ready  for  adjustment  in  the 
mouth.  The  unsoldered  end  of  the  joint  permits  the  collar  to 
be  easily  and  accurately  adapted  to  the  root,  after  which  the 
solder  can  be  flowed  across  the  collar  and  the  joint  closed. 

When  the  collar  has  been  formed,  it  is  adjusted  on  the  root 
and  pressed  or,  by  the  aid  of  a  piece  of  wood,  one  end  of  which 


Fig.  151. 


Fig.  152. 


is  placed  across  the  outer  edges  of  the  collar,  tapped,  up  to  the 
margin  of  the  gum.  A  line  parallel  with  the  margin  is  marked 
with  a  sharp-pointed  instrument  on  the  collar  (A,  Figs.  153  and 


88 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  155. 


154),  which  is  then  removed,  trimmed  to  this  mark,  readjusted, 
and  again  marked  (B),  and  the  process  continued  until  the  col- 
lar fits  proportionately  under  the  margin  of  the  gum.  If,  on 
adjusting,  the  collar  is  found  a  trifle  too 
small,  it  is  easily  enlarged  by  tapping  the 
gold  with  a  riveting  hammer  on  an  anvil 
as  shown  in  Fig.  155.  If,  on  the  con- 
trary, the  collar  should  prove  to  be  too 
large  in  circumference,  the  difficulty  can 
be  remedied  by  slitting  the  gold  partly 
across  the  side  opposite  the  joint,  lapping 
the  edges  slightly,  and 
soldering.  The  edge  is 
then  burnished  to  the 
periphery  of  the  root. 
For  this  purpose  a  set 
of  burnishers  should  be 
used  especially  formed 
to  suit  the  different  posi- 
tions and  avoid  irrita- 
tion of  the  margin  of  the  gum 
Fiff.  156. 


Such  a  set  is  illustrated  by 


Fig.  ISfi. 


The  application  of  local  anesthetics  such  as  cocaine,  carbolic 
acid,  or  a  mixture  of  tincture  of  aconite-root  and  chloroform, 
will  lessen  the  pain  attending  the  operation. 


I 


CHAPTER  VII. 

GOLD   COLLAR   CROWNS   WITH   PORCELAIN   FRONTS. 
INCISORS    AND    CUSPIDS. 


This  style  of  crown  for  incisors  and  cuspids,  as  originally  made 
by  Dr.  C.  M.  Richmond,  and  with  which  his  name  has  become 
associated,  consisted  of  a  cap  for  the  root,  formed  of  a  band  of 
gold  capped  with  platinum  on  which  was  soldered  a  tooth  with 
a  slot  in  the  center  between  the  pins.  Through  this  slot  and  the 
center  of  the  cap  a  screw  passed  which  entered  into  a  cylinder 
previously  screwed  and  cemented  into  the  root-canal. 

The  form  of  gold  collar  crown  in  general  use  at  present  is,  in 
principle,  the  same  as  what  has  been  known  in  dentistry  as  a 
gold  pivot  tooth,  with  the  addition  of  a  gold  collar  for  the  rootr 
and  having  the  advantage  of  oxyphosphate  for  its  cementation. 
These  improvements,  however,  enhance  its  value  as  a  crown,, 
and  materially  change  the  process  of  its  construction.  'In 
making  an  incisor  or  cuspid  crown  of  this  style,  the  collar,, 
having  been  formed,  is  trimmed  even  with  the  surface  of  the 
end  of  the  root.  With  the  collar  in  position  on  the  root,  a 
corundum-wheel  is  passed  over  the  labial  edge,  along  the  margin 
of  the  gum,  to  level  the  gold  with  the  root  and  render  it  invisible 
when  the  crown  is  finished.  /  The  work  will  then  present  the 
appearance  shown  in  Fig.  157. 

The  cap  is  made  by  adapting  the  surface  of  a  very  thin  piece 
of  platinum  plate/to  the  outer  edge  of  the  collar,  and  uniting 
them  with  solder  in  the  flame  of  a  lamp  (Fig.  158).  The  quan- 
tity of  solder  used  must  be  very  small,  and  it  should  be  placed 
on  the  platinum  outside  of  the  collar,  as  otherwise  it  will  flow 
over  the  inside  of  the  collar  and  interfere  with  the  fit  of  the  cap. 
The  process  is  facilitated  by  first  merely  attaching  the  platinum, 
with  the  solder,  to  the  edge  of  the  collar,  then  readapting,  and 

89 


90 


ARTIFICIAL  a 


\\-  AXD  BRIDGE-WORK. 


*£ 


finishing  the  soldering.  The  platinum  is  then  trimmed  to  the 
collar,  and  the  rap  adjusted  on  the  root.  The  labial  section  of 
the  surface  of  the  cap  is  then  burnished  to  the  end  of  the  root 
(A,  Fig.  157).  The  root-canal  having  been  slightly  enlarged,  a 
pin  of  round  iridio-platinum  wire,  No.  16  or  17,  U.  S.  standard 
gauge, — filed  a  little  smaller  for  laterals  or  other  roots  which 
require  it, — is  slightly  tapered  at  the  point,  fitted  to  an  aperture 
made  in  the  cap,  and  to  the  canal  (B).  The  pin  is  then  cut  off 
even  with  the  cap,  removed,  and  temporarily  laid  aside. 

A  hollow  wire,  the  open  space  in  the  center  of  which  is  very 
small,  has  lately  been  introduced  for  use  in  crown-work  by 
Dr.  J.  G.  Morey.  The  advantage  it  confers  is  the  comparatively 
easy  manner  in  which  it  can  be  drilled  out  of  the  canal  if  for 


Fig.  157. 


Fig.  158. 


Fig.  159. 


Fig.  160. 


any  reason  it  becomes  necessary  to  remove  the  crown,  as  the 
drill  will  follow  the  fine  opening  in  the  center  of  the  wire. 

A  plain-plate  cross-pin  tooth,  suitable  in  form  and  color,  is 
ground  and  fitted  in  position  on  the  cap.  The  labio-cervical 
edge  of  the  porcelain  (A,  Fig.  159)  should  be  flush  with  the  edge 
of  the  collar,  and  meet  the  margin  of  the  gum.  It  should  be 
cut  out  at  the  base  (I!)  so  as  to  form  a  slight  space  just  over  the 
end  of  the  pin.  The  tooth  is  then  backed  with  yerfrthtn  pure 
gold,  gold  lined  with  platinum,  or  pure  platinitfn.  Platinum 
fainl  blue  shade,  and  gold,  or  gold  lined  with  platinum, 
If  the  gold  ,-idc  is  toward  the  porcelain,  a  slight  yellow  shade 
The  backing  should  extend  as  far  a<  possible  under  and  between 
the  tooth  and  the  cap,  a-  the  solder  will  How  in  and  till  the  space, 
thus  giving  strength  and  continuity  of  structure.  The  backing, 
it'  bent  over  the  incisive  edge  ((')  at  a  right   angle,  will   protect 


COLLAR  CROWNS   WITH  POJiCKLMS  FROSTS.  \\\ 

the  porcelain  in  occlusion.  A  narrow  strip  of  fine  'gold  placed 
transversely  across  at  that  point  previous  to  investing,  and  united 
in  the  soldering  of  the  backing,  will  answer  the  same  purpose. 

The  tooth,  when  backed,  is  secured  in  position  on  the  cap 
with  a  compound  of  wax  and  resin,  and  the  whole  adjusted  in 
the  mouth,  then  removed,  and  the  pin,  which  has  been  laid 
aside,  warmed  and  placed  in  position  by  passing  the  end  from 
the  inside  of  the  cap  through  the  hole  into  the  wax  attaching 
the  porcelain  crown.  Another  adjustment  in  the  mouth  is  then 
made  to  determine  the  exact  line  for  the  pin,  and  the  case  is 
ready  for  investment. 

After  the  fitting  of  the  pin  to  the  root  and  root-canal,  as  has 
been  described  when  the  cap  was  formed,  some  prefer  to  solder 
it  to  the  cap,  for  which  purpose  it  should  be  adjusted  in  position 
and  cemented  with  wax,  then  removed,  invested,  and  soldered 
(Fig.  160).  At  this  stage  of  the  work,  if  desired,  an  impression 
•can  be  taken  in  a  small  impression  cup  (Fig.  161)  with  cither 
plaster  or  modeling  compound.     The  cap  should  be  removed  in 


Fin.  161. 


Fig.  162. 


Fio.  163. 


position  in  the  impression.  To  aid  this,  a  piece  of  gutta-percha 
can  be  put  on  the  end  of  the  pin  projecting  from  the  cap.  An 
articulation  of  the  lower  teeth  should  also  be  obtained.  When 
the  model  is  made,  the  pin  is  cut  off  even  with  the  cap,  and  the 
porcelain  tooth  fitted  as  already  described. 

Calcined  marble-dust  and  plaster,  in  the  proportion  of  two 
parts  of  marble-dust  to  one  of  plaster,  to  which  is  added  a  pinch 
of  sulphate  of  potassium  to  quicken  the  setting,  makes  what  is 
considered  to  be  the  most  suitable  investing  material  for  crown- 
work.     The  crown,  when  invested,  should  be  left  exposed  at  the 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


92 


sides,  as  illustrated  in  Fig.  162.     The 

in  the  direction  A.  and  the   investment   heated  /uniformly, 

tfa^fc  thw  colder  is  flowed  between  the  porcelain  erown  and  the 


/ 


Only  sufficient  gold  should  be  used  to  insure  restoration 
of  contour.  When  soldered,  after  having  been  placed  in  acid 
and  thoroughly  divested  of  borax,  the  crown  is  ready  for  the 
finishing  and  polishing  process.  Fig.  163  represents  the  com- 
pleted crown. 

BICUSPIDS    AND    MOLARS. 

Bicuspids  crowned  by  this  method  will  have  greater  strength 
if  a  portion  of  the  palatal  section  of  the  natural  crown  is  reserved 
(Fig.  22),  and  the  band  or  collar  made  deep  enough  to  cover  it. 

The  end  of  the  root  is  capped  after  the  manner  of  the  typical 
central  already  described,  one  or  two  pins  being  used  in  the 
canals  as  required.      A  porcelain  cuspid  tooth,  or  a  bicuspid 


Fig.  164. 


Fig.  165. 


Fig.  160. 


Fig.  168. 


front,  is  then  ground,  backed,  and  adjusted  on  the  cap  to  repre- 
sent the  labial  aspect,  and  secured  with  wax.  The  front  and 
cap  are  then  removed,  invested,  and  soldered,  after  which  they 
are  adjusted  in  the  mouth,  and  the  occluding  edge  of  the  por- 
celain is  ground  clear  of  the  antagonizing  teeth  (A,  Fig.  JL64). 
With  a  die  of  suitable  size  representing  the  occluding  sur- 
face of  a  bicuspid,  as  illustrated  in  Fig.  165,  a  thin  piece  of  pure 
.gold  plate  is  -waged  (Fig.  166)  and  the  cusps  filled  in  with  18-  or 
20-caratgold  plate.  The  cap  is  then  trimmed  (Fig.  167). ground, 
and  fitted  to  the  occluding  edge  of  the  porcelain  front  (Fig.  168) 
in  proper  position  .as  regards  occlusion,  and  the  wax  attaching 
it  u  Bhaped  to  the  contour  of  the  crown  (A).  A  piece  of  pure 
gold  plat  B  .  not  over  34  or  35  IT.  S.  standard  gauge,  ie  then 
adjusted  on  each  Bide  of  tin;  erown.  which  is  invested  (Fig.  169). 


IfV^ 


)LD  COLLAR  CROWNS  WITH  PORCELAIN  FRONTS. 


93 


The  long  ends  of  the  two  side-pieces  of  gold  plate  are  designed 
to  retain  them  in  position,  as  the  investing  material  should  be 
removed  from  the  portion  inclosing  the  sides  of  the  crown  (A). 
In  the  process  of  soldering  the  solder  is  placed  in  the  aperture 
at  B,  and  the  flame  of  the  blow-pipe  being  directed  on  the  ex 
posed  sides  of  the  gold  at  A,  the  solder  is  flowed  into  every 
part,  forming  perfect  continuity  of  structure  of  the  metallic  per 
tion  of  the  crown.  \ln  finishing,  the  surplus  gold  is  trimmed  to 
the  contour  of  a  bicuspid  tooth.  Fig.  170  represents  the  finished 
crown. 

The  method  described  produces  a  perfect  and  artistically 
farmed  crown,  but  simpler  and  quicker  methods  are  practiced. 
One  of  these  is  to  build  up  the  palatal  cusp  with  several  pieces 
_rold  plate,  which  have  been  previously  melted  into  the  form 
<>f  small  balls  and  flattened  out  on  an  anvil.  These,  laid  in  posi- 
tion and  united  with  solder,  are  shaped  in  finishing  to  represent 

Fig.  170.  Fig.  171.  Fig.  172.  Fm.  173. 


the  palatal  cusp  (Fig.  171).  The  porcelain  front  should  be 
backed  so  that  the  solder  can  be  fl  >wed  over  its  occluding  ed^e. 

Another  method  is  to  extend  the  palatal  part  of  the  collar  down 
as  shown  in  Fig.  172,  and  then  fill  in  the  space  with  solder. 
In  finishing,  the  gold  is  trimmed  to  the  form  of  the  crown.  In 
this  and  in  the  method  just  previously  described,  the  porcelain 
front  can  be  soldered  and  the  palatal  cusp  formed  in  the  one 
investment. 

The  method  of  construction  of  molar  crowns  with  porcelain 
fronts  is  similar  to  that  for  bicuspids  (Fig.  173). 

Dr.  StoweWs  Method. — A  porcelain  crown  can  be  soldered 
o:i  the  cap,  according  to  Dr.  S.  S.  Stowell's  method,  as  follows  :  ' 
••  The  tooth  used  may  be  a  Logan  or  an  E.  Parmly  Brown  crown 

1  Dental  Cosmos,  vol.  xxix,  page  G41. 


94 


A/tTIFiri.iL  CROWN-  AXD  BRIDGE-W< )RK. 


or  an  ordinary  countersunk  tooth,  but  in  most  cases  the  Logan 
crown  is  preferable.  The  pin  is  first  cut  off,  then  the  tooth  is 
ground  to  fit  on  the  cap,  porcelain  and  the  stump  of  the  pin 
being  reduced  alike  evenly  and  smoothly  ;  after  which  the  stump 
of  the  pin  is  ground  with  a  small  wheel  below  the  surface  of 
the  porcelain  (Fig.  174).  The  tooth  is  then  invested  (Fig.  175) 
and  pure  gold  fused  on  to  the  platinum  pin,  and  while  in  a  fluid 
state  it  is  with  a  wax  spatula  '  spatted '  down  flat  (Fig.  176). 
The  gold  is  then  filed  or  ground  down  even  with  the  porcelain, 


Fig.  174. 


Fig.  175. 


Fig.  176. 


Fig.  177. 


Fig.  178. 


ami  at  the  palatal  border  the  tooth  is  ground  to  bevel  back  until 
the  gold  is  reached  (Fig.  177).  The  tooth  is  then  secured  in 
place  on  the  cap  with  wax  cement  (Fig.  178),  the  case  invested, 
and  heated  until  the  wax  has  melted  and  burned  out.  A  small 
clipping  of  thin  platinum  plate  is  crowded  into  the  opening  (Fig. 
179)  caused  by  the  grinding  of  the  bevel  on  the  cf own.  The 
clipping  of  platinum  serves  as  a  lead  for  the  solder,  which  fol- 
lows it  down  into  the  countersunk  cap,  around  the  ends  of  the 
dowels,  and  finally  attaches  itself  to  the  pure  gold  already  at- 
tached to  the  stump  of  the  platinum  pin.  Fig.  180  represents 
the  completed   crown.     A  sectional  view  of  a  like  crown  (Fig. 

Fig.  179.  Fin.   18^.  Fig.   181.  Fig.  182.  Fig.  183. 


181)  also  shows  the  organization  in  detail.     A  porcelain  crown 
can  be  used   to  represent  any  of  the  teeth  in  the  -nine  manner. 

Fie  .  L82  ;m,.|  L83." 


,   ^ 


^J&^KY 


PTER  VIII. 


Fio.    1H1. 


ALL-GOLD  COLLA.R  CROWDS  FOR  BICUSPIDS  AND  MOLARS 
CONSTRUCTED  IN  SECTIONS.  -  1vt  04-A-<r>-a 
\ 

The  root  and  crown  having  fteen  properly  prepared,  the  collar 
is  formed  and  adjusted  as  described  at  page  85,  and  the  edge 
toward  the  antagonizing  teeth  trimmed,  to  fully  clear  them  in 
occlusion.  The  collar  is  then  slightly  expanded  toward  the 
occluding  surface  to  effect  contour/ removed,  filled  with  plaster, 
and  adjusted  in  position.  Fig.  184  rep- 
resents a  typical  case.  The  antagonizing 
teeth,  having  been  covered  with  a  piece 
of  tin  foil,  are  then  occluded  until  the 
plaster  sets.  The  collar  is  then  removed. 
The  surface  of  the  plaster  inside  the 
collar  will  give  the  impression  of  the 
natural  root  or  crown,  and  the  outside 

that  of  the  antagonizing  teeth.     The  latter  furnishes  an  outline 
of  the  grinding-surface  of  the  crown. 

The  plaster  is  then  trimmed  and  shaped  to  represent  the  cusps 
and  fissures  of  the  natural  tooth,  enough  of  the  surface  being- 
removed  to  allow  for  the  thickness  of  the  plate  that  forms  the 
cap.  Readjustment  in  the  mouth  will  show  the  accuracy  of 
the  occlusion. 

A  small  tube  of  copper,  a  trifle  larger  in  circumference  than 
the  crown  under  construction,  is  tilled  with  Melotte's  "  moldine," 
and  the  surface  rubbed  with  soapstone.  An  impression  of  the 
lower  portion  of  the  form  of  the  crown  A  to  the  line  B,  Fig.  185. 
is  then  made  in  the  moldine,  and  a  strip  of  paper  wound  around 
the  tube,  extending  about  an  inch  above  the  edge.  Fusible  alloy 
is  then  melted  and  poured  into  the  mold,  thus  forming  a  die. 

95 


96 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fin    18-3. 


Fm    186. 


An  indentation  is  made  with  a  punch  in  a  block  of  lead,  into 
which  the  die,  when    cold,  is   hammered  slightly  beyond  the 

impression  of  the  edge  of  the 
collar.  By  this  method  a  die 
and  a  counter-die  (Fig.  186)  can, 
with  practice,  be  completed  in 
five  minutes.  With  this  die  the 
cap  is  then  struck  up  on  the 
lead  from  a  flat  piece  of  plate 
and  fitted  to  the  collar.  A 
little  of  the  surface  of  the 
plaster  in  the  collar  may  have 
to  be  removed,  if,  on  trial  in 
the  mouth,  the  cap  is  found  a 
little  flush.  The  crown,  with 
the  plaster  still  inside  the  collar,  is  fixed  in  a  soldering  clamp 
constructed  in  one  of  the  forms  shown  in  Figs.  187  and  188, 
which  holds  the  parts  together  and  permits  the  flame  to  reach 
all  points.  No  more  solder  should  be  used  than  the  contour 
requires,  as  an  excess  necessitates  additional  labor  in  finishing. 

Another  method,  if  the  crown  is  not  to  be  contoured  with  the 
aid  of  the  solder,  is,  when  the  cap  is  struck  up,  to  melt  solder 
into  the  cusps,  and  then  adjust  the  cap  in  position  on  the  collar, 
for  which  purpose  some  of  the  plaster  underneath  the  cap  must 
be  removed.  A  jet  of  flame  from  the  blow-pipe  is  then  thrown 
Pig.  187.  Fig.  188. 


A,  Fusible  die. 

B,  Counter-die. 

C,  Plate  to  form 
the  cup. 


I  v   frame  of  ilii-  clamp  i-  formed  <>f  iron  wire,  and  the 
rapport  for  the  crown  of  plaster,  asbestos,  and  marble-dost. 


upon  it  in  BUCh  ;i  w;ty  ;is  to  cause  Hi''  solder  to  How  down  on  (lie 
edge  of  the  collar  and  fill  the  Beam  from  the  inside.  The  objection 
to  this  method  is  that,  when  a  large  portion  of  the  natural  crown 
i~   inclosed    by   the  gold,  the  solder  will   occasionally   niter  the 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.    97 


inside  form  of  the  fitted  cap,  thereby  interfering  with  its  adjust- 
ment, which  is  a  defect  troublesome  to  correct. 

Still  another  method  is  to  adjust  the  collar  in  the  mouth,  and, 
with  a  small  piece  of  wax  or  impression-compound  pressed 
upon  it,  to  take  an  impression  and  "  bite,"  in  which  the  collar 
will  be  imbedded  and  removed.  "With  this  a  model  and  articu- 
lation are  made  and  the  form  of  the  cap  shaped  in  wax.  An 
impression  of  the  cap  is  then  made,  either  in  moldine  in  a  soft 
state  in  a  tube,  or  in  plaster,  and  a  die  cast.  The  cap  is  stamped 
on  this  die,  then  adapted  to  the  collar  by  the  model,  and  the 
crown  finished.  This  method,  which  was  first  made  known  by 
Dr.  1ST.  W.  Kingsley,  is  adopted  when  it  is  preferable  to  construct 
the  crown  between  the  visits  of  the  patient. 

In  utilizing  a  tooth  as  an  abutment  in  bridge-work  when  all 
or  nearly  all  of  the  occluding  surface  of  the  natural  crown  is 
present,  a  practical  method  of  construction  is  to  mark  the  out- 
line of  the  natural  crown  on  the  inner  surface  of  the  collar; 
then  remove  the  collar  and  trim  so  as  to  leave  a  border  of  about 
one-sixteenth  of  an  inch  outside  the  mark.     This  border  is  then 


Fig.  190. 


Fig.  191. 


thinned  with  a  corundum-wheel,  and  slit  as  seen  in  Fig.  189. 
The  collar  is  next  adjusted  on  the  crown,  and  the  slit  border 
bent  over  to  the  form  of  the  occluding  surface,  to  which  it  is 
burnished.  A  piece  of  pure  gold  plate,  about  ~No.  34  gauge,  is 
then  placed  on  the  occluding  surface  of  the  tooth  and  adapted  to 

7 


98 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


it  and  to  the  collar.  The  gold  may  first  bo  struck  in  the  form 
of  a  cap  by  laying  it  on  a  block  of  lead  and  hammering  into  it 
a  die  corresponding  to  the  surface  of  the  tooth  to  be  crowned 


(Fig.  190).  Tin-  antagonizing  teeth  are  then  occluded  on  the 
eold,  which  i>  thereby  pressed  to  form  to  articulate  with  the 
occluding  surfaces.      Enough  of  the  occluding  surface  of  the 

tooth  crowned  should  always  l»e  removed  t<>  allow  for  the  thick- 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.     99 


ness  of  the  gold  covering  its  surface.  The  collar  and  cap  are 
next  removed  and  soldered.  This  is  done  by  resting  the  collar 
on  the  cap,  which  is  held  by  a  pair  of  tweezers,  or  by  clamping 
the  cap  and  collar  together  and  placing  the  solder  in  small  pieces 
around  the  collar  outside  the  cap,  at  A,  Fig.  191,  and  soldering 
by  holding  in  a  blue  gas  flame.  Only  sufficient  solder  should 
be  used  to  join  and  ti.ll  the  seams,  so  that  it  will  not  interfere 
with  adjustment  on  the  natural  crown. 

The  methods  described  insure  a  perfect  occlusion  of  the  crown 
with  the  antagonizing  teeth.  In  the  absence  of  antagonizing 
teeth,  or  when  the  general  form  of  the  grinding-surface  permits 

Fig.  193. 

C  A  B 


it,  the  cap  can  be  struck  up  with  a  die  similar  to  the  one  shown 
in  Fig.  190.  The  cusps  are  then  filled  in,  and  the  edges  of  the 
inner  surface  of  the  cap  ground  level  on  the  side  of  a  corundum- 
wheel.  The  entire  circumference  of  the  edge  of  the  collar  is 
also  leveled,  and  the  cap  adjusted,  clamped,  and  soldered.  If 
the  cusps  of  the  cap  are  filled  in  with  solder,  it  will  flow  down 
and  join  the  collar  on  the  inside ;  if  with  gold  plate,  the  cap  and 
collar  must  be  joined  with  solder  either  on  the  inside  or  outside. 
Metallic  caps,  or  forms  of  the  occluding  surfaces  of  teeth  for 
use  in  constructing  crowns,  are  quickly  made  with  the  die-plate 
shown  in  Fig.  192,1  "in  which  are  four  groups  of  intaglio  dies 
representing,  with  distinctive  correctness,  the  peculiar  cusps  of 

1  Dental  Cosmos,  vol.  xxix,  page  482. 


100 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  104. 


the  upper  and  lower  right  and  left  bicuspids  and  molars.  These 
are  indicated  by  the  Hillischer  notation,  so  that  each  form  may  be 
easily  identified  in  practice.  The  hubs  A,  B  (Fig.  193)  are  of  the 
sizes  shown,  and  are  made  of  an  alloy  composed  of  tin  one  part, 
lead  four  parts,  melted  together.     The  mold  C  should  be  warmed, 

the  metal  alloy  poured  in 
every  hole,  and  the  overflow 
wiped  off  just  before  the 
metal  stiffens:  this  will  make 
the  butts  of  the  hubs  smooth 
and  flat.  After  a  minute  or 
two  the  mold  may  be  re- 
versed, the  hubs  shaken  out, 
and  the  casting  process  con- 
tinued until  a  considerable 
number   of  hubs  shall  have 


been  made.  In  Fig.  194  a 
molar  hub  is  shown  in  place  on  a  piece  of  No.  32  gold  plate, 
which  lies  over  the  6*  (upper  right  first  molar)  die.  A  succes- 
sion of  blows  on  the  hub  with  a  four-pound  smooth-face  ham- 
mer will  drive  the  plate  into  the  die,  and,  at  the  same  time, 
spread  the  hub  metal  from  the  die  center  to  its  circumference,  in 

Ftg.  195. 


Buch  a  manner  that  the  plate  will  be  perfectly  struck  up  with 
the  least  possible  risk  of  being  cracked.  The  flattened  hub  is 
seen  in  Fig.  195,  which  also  shows  at  D  the  obverse  of  the  s truck- 
up  huh.  and  at  El  the  cameo  of  the  struck-up  plate,  having  every 
cusp  and  depression  of  6*  sharply  defined.    The  counter-die  plate 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.  101 

(Fig.  192)  is  made  of  a  very  hard  cast  metal,  which  will  admit  of 
the  striking  up  of  many  crown  plates  by  the  means  described, 
if  the  crown  plates  be  not  too  thick  and  stiff.  Of  course  they 
should  be  annealed  before  they  are  placed  over  the  die. 


r-l 


i  *- 1 


r  ^1 


L<, 


<\ 


I  -sq 


* 


s 
-a 


t: 


O      i  *o 


-*J 


"  In  careful  hands  the  die-plate  should  give  clear  cusp  defini- 
tions after  years  of  use.  The  counter-die  plate  is  in  some  re- 
spects similar  to  a  stereotype  plate  for  printing,  and  the  struck 


102 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


impressions  on  two  strips  of  thin  plate  will  therefore  appear  as 
in  Fig.  196,  wherein  their  regular  order  is  noticeable,  as  seen 
from  the  cameo  surface  of  the  struck  plates. 

"  The  peculiar  action  of  the  hub  in  forming  first  the  center  of 
the  crown  plate,  and  spreading  from  the  center  outwards,  as  the 
hub  is  shortened  under  the  hammer,  until  the  die  is  overspread 
by  the  plate  and  hub,  with  the  result  shown  in  Fig.  195,  is  an 
essential  feature  of  this  process  for  obtaining  easily  and  quickly 
the  superior  styles  of  coronal  cameos  shown.  If  a  cusp  or 
fissure   should  chance    to   crack  in  hubbing,  a   small  piece  of 


Fig.  197. 


plate  may  be  struck  up  over  the  fissure,  and  then  soldered  to  the 
^jiginal  cap." 

The  methods  which  have  been  described  for  the  construction  of 
all-gold  bicuspid  and  molar  crowns  are  those  generally  adopted 
in  practice.  Of  others,  Dr.  J.  J.  R.  Patrick's  method1  consists 
of  first  forming  a  very  narrow  collar  and  telescoping  it  with  a 

unless  cap  of  the  form  of  the  crown,  and  soldering  along  the 
line  of  the  cap  to  the  collar. 

JJr.  E.  P.  Brown's  method  i>  to  make  or  select  a  metallic  die 
for  the  crown  to  be  formed;  then  place  a  piece  of  pure  gold 
plate,  about  No.  31  gauge,  on  the  flat  surface  of  a  Mock  of  lead, 
and  gradually  Stamp  the  die  downward  into  the  gold  to  about 

•Dr.  Patrick's  crown-work  methods  and  the  principles  upon  which  they  are 
based  are  set  forth  in  a  puper  published  in  the  Dental,  Cosmot  t»r  October,  1888, 
page  706. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.  103 


half  the  depth  of  the  intended  crown.  The  gold  is  then  re- 
moved, and  each  side  of  the  unswaged  portion  slit  and  adapted 
to  the  form  of  the  die,  the  full  length  of  the  crown,  which  is 
then  adjusted  in  the  mouth,  the  edges  of  the  gold  trimmed  to 
the  proper  form,  and  the  slits  soldered. 

Dr.  M.  liyn ear's  crown  is  of  the  same  general  character  and 
is  constructed  in  the  same  manner  as  Dr.  Brown's,  except  that  a 
seamless  cap  is  used  to  form  the  crown,  instead  of  the  flat  piec 
of  plate  used  by  Dr.  Brown. 


Fig.  197  represents  a  case  of  abrasion  of  the  lower  teeth,  to 
which  all-gold  crowns  have  been  applied,  as  shown  in  Fig.  198. 
In  such  cases,  owing  to  the  aggression  of  the  occluding  teeth, 
the  cap  forming  the  occluding  surface  should  be  constructed  of 
heavy  gold  and  platinum  plate.  An  artificial  plate  replaces  the 
upper  teeth. 


it 


CHAPTER    IX. 

THE   GOLD   SEAMLESS   CAP   CKOWN. 

This  method  consists  in  the  use  of  a  gold  seamless  cap  for  the 
construction  of  the  required  root  cap  or  crown. 


INCISORS,   CUSPIDS, 


AND    BICUSPIDS,  WITH   PORCELAIN 
FRONTS. 


Fig.  200. 


Incisor,  cuspid,  and  bicuspid  crowns  with  porcelain  fronts  are 
constructed  by  this  method  as  follows :  The  natural  crown  is 
ground  down  to  within  about  one-eighth  of  an  inch  of  the  gum 
at  the  palatal  wall,  or  enough  to  clear  the  antagonizing  teeth 
when  occluded,  and  slanting  from  the  posterior  edge  of  the 
pulp-chamber  to  the  cervico-labial  edge  of  the  gum  and  slightly 
under  its  margin  if  it  is  desirable  to  conceal  the  joining  of  the 
crown  with  the  root.  The  sides  are  shaped  the  same  as  for  a 
collar  crown  (Fig.  199).  A  die  of  the  end  of  the  root  is  then 
made.  For  this  purpose  an  impression  of  the  part  is  taken  with 
gutta-percha  on  the  end  of  a  piece  of  wood 
trimmed  to  the  proper  size,  or  by  placing 
tin*  gutot-pereha  in  a  tube  formed  of  a  strip 
of  copper  about  one  and  one-half  inches  in 
length  and  three-eighths  of  an  inch  in  di- 
ameter, cut  out  on  the  sides  to  the'  depth  of 
half  an  inch,  with  the  flange  for  the  palatal 
side  shortened  (Fig.  200).  The  impression 
thus  taken  will  he  confined  almost  entirely 
to  the  end  of  the  root  to  be  capped.  When  J 
the  gutta-pon-lm  wfeH,  A  st rip  of  paper  is  tied  around  the 

wood  or  tube  and  a  die  east  with  the  fusible  metal.  \  When  cool, 
the  die  U  removed  from  the  mold,  and  the  metal  is  trimmed, 
with  file  and  chisel,  a  little  deeper  than  the  gum  has  permitted 

the  impression  Of  the  root  to  be  taken,  and  without  altering  the 
104  . 

- 

/    _ 


* 


/ 


riU 


V 


THE  GOLD  SEAMLESS  CAP  CROWN. 


105 


form  of  the  end  of  the  root  (Fig.  201).  A  counter-die  is  then 
made  by  punching  a  hole  in  the  surface  of  a  block  of  pure  lead, 
and  with  a  few  blows  of  a  hammer  driving  the  die  into  it. 

A  cap  of  gold  can  be  formed  by  placing  a  piece  of  gold  plate 
(preferably  pure,  No.  32  U.  S.  standard  gauge)  of  suitable  size 
upon  a  block  of  lead,  and  with  an  oval-shaped  punch  one-fourth  of 
an  inch  in  diameter  gradually  driving  it  into  the  lead  until  the  gold 
has  assumed  the  shape  of  a  cap  about  a  quarter-inch  in  depth  (A, 
Fig.  201).  The  gold  should  be  withdrawn  from  under  the  punch 
and  annealed  several  times  during  the  process.  Caps  can  also  be 
made  with  a  stamping-press  such  as  was  introduced  by  Dr.  J.  J. 
R.  Patrick,  of  Belleville,  111.     (See  page  112.) 


Fig.  201. 


Fig.  202. 


Fig.  204. 


Fig.  203. 


The  cap  is  then  annealed  and  swaged  on  the  die  to  the  form 
of  the  end  of  the  root  (B,  Fig.  201).  The  palatal  portion  of  the 
cap  should  be  allowed  to  go  well  up  under  the  free  edge  of  the 
gum,  and  at  the  cervico-labial  edge  it  can  be,  if  preferred,  cut  out 
to  the  edge  of  the  root.  In  the  process  of  adjustment,  the  edges 
which  fit  under  the  gum  should  be  marked  and  trimmed  as 
directed  in  describing  the  construction  of  a  collar  crown,  and 
then  burnished  close  to  the  sides  of  the  root  and  into  the  orifice 
of  the  root-canal,  forming  a  perfect-fitting  seamless  cap  (Fig. 
202).  An  iridio-platinum  pin  is  then  fitted  in  the  root-canal  and 
soldered  to  the  cap  (Fig.  203),  or  afterward  adjusted  as  in  the 


106  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

construction  of  the  gold  collar  crown  with  porcelain  front  (page 
90),  with  which  operation  the  remainder  of  the  process  of 
construction  is  identical.  Fig.  204  represents  the  completed 
crown. 

The  advantages  of  this  style  of  crown  are,  simplicity,  as  the 
formation  of  a  collar  is  avoided,  and  strength,  as  a  large  portion 
of  the  natural  crown  can  be  left  at  the  palatal  side.  This  affords 
a  stronger  and  more  reliable  foundation  than  can  be  obtained  at 
any  other  point,  as  the  direction  of  the  force  in  mastication  is 
forward  at  an  angle  with  the  line  of  the  root,  and  although  the 
gold  of  the  cap,  where  it  encircles  the  root  at  the  cervi co-labial 
edge,  is  entirely  removed,  the  crown  is  still  held  securely. 

In  a  paper  on  the  subject  of  preserving  and  utilizing  this  part 
of  the  tooth,  Dr.  W.  F.  Litch,  of  Philadelphia,  describes  a 
crowning  operation.1  lie  constructed  the  cap  of  platinum  by 
slitting  a  piece  of  the  plate  in  a  number  of  places,  adapting  it  to 
the  form  of  the  end  of  the  root,  and  then  soldering  the  whole 
together. 

This  operation  is  not,  however,  so  easily  or  so  satisfactorily 
performed  as  the  method  above  described,  in  which  platinum,  if 
desired,  can  be  used  instead  of  gold,  and  the  soldering  done  with 
22-  or  24-carat  gold.  In  some  respects  pure  platinum  is  prefer- 
able to  gold  in  capping  roots,  as  it  is  less  likely  to  be  affected  by 
the  secretions  of  the  mouth. 

ALL-COLD   BICUSPIDS    AND    MOLARS. 

/ 

All-gold  seamless  crowns  for  bicuspids  and  molars  that  will 
accurately  fit  the  natural  crown  and  root,  and  occlude  properly 
with  the  antagonizing  teeth,  are  easily  and  quickly  formed,  if 
sufficient  of  the  natural  crown  remains  to  admit  of  temporary 
restoration  of  its  contour  with  gutta-percha  or  any  other  suit- 
able plastic  material...  When  this  has  been  done,  an  impression 
of  the  restored  tooth  ie  taken  in  /gutta-percha  in  a  tube,  as  ex- 
plained on  page  104,  and  a  die  then  formed  of  fusible  alloy;  or 
a  plaster  model  can  be  made  from  an  impression  of  the  tooth 

taken  in  wax,  and  a  mold  obtained  from  the  model. 
The  preparation  and  shaping  of  the  natural  crown  to  receive 


1  Denial  CosmOBf  vol.  x\v.  No.  9,  pago 


THE  GOLD  SEAMLESS  CAP  CROWN. 


107 


the  artificial  crown  can  then  be  proceeded  with.  Where  the 
natural  crown  is  very  badly  decayed  or  broken  down  and  the 
method  just  described  is  not  practicable,  the  portion  of  the 
natural  crown  or  root  remaining  should  be  shaped  and  prepared 
to  receive  an  artificial  crown.  Then  the  form  of  the  cervix  is 
ascertained  with  a  wire  as  described  on  page  86,  and  an  impres- 
sion of  the  parts  taken  in  wax,  and  the  wire  form,  the  twisted 
ends  having  been  shortened,  is  carefully  adjusted  on  the  wax  at 
the  cervical  line.  The  plaster  model,  when  made,  will  show  the 
wire  slightly  imbedded  in  the  plaster.  The  plaster  should  be 
trimmed  to  the  inner  edge  of  the  wire,  as  that  represents  the 
exact  form  of  the  root  (Fig.  205). 

Another  method  is  to  encircle  and  adapt  to  the  form  of  the 
root  a  strip  of  annealed  copper,  No.  35  standard  gauge,  about 


Fig.  205. 


Fig.  206. 


one-eighth  of  an  inch  wide/Y'rhe  copper  is  then  removed,  the.  ■ 
^ndgJi£^tfrLgjifl:^''*^ir>ilI^fl  wHh  '^n  aHA™.^  the  copper  adjusted 


on  the  root,  and  tin-  ends  cemented  with  a  warm  instrument. 
An  impression  is  next  taken  with  plaster,  in  which  the  copper 
band  is  removed  in  position.  A  model  made  from  this  impres- 
sion, after  the  copper  is  removed,  presents  the  exact  form  of  the 
root. 

From  a  "  bite  "  taken  in  wax  a  plaster  articulation  is  then  made 
to  the  model.  A  hole  is  then  drilled  in  the  center  of  the  form 
of  the  root  on  the  model  to  be  crowned.  In  this  hole,  and  over 
the  end  of  the  root,  a  ball  of  soft  plaster,  slightly  colored  with 
carmine,  is  placed,  and  the  teeth  of  the  articulation,  covered 
with  tin  foil,  closed  on  it.  This,  on  separation,  gives  the  outline 
of  the  form  of  the  grinding-surface  for  the  crown.     The  sides  of 


108 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


the  plaster  are  then  trimmed  to  the  form  of  the  crown,  and  the 
whole  carved  in  detail  (Fig.  206).  As  the  crown  will  always 
stamp  larger  in  circumference  than  the  die,  in  proportion  to 
the  thickness  of  the  gold  used,  an  allowance  must  be  made 
by  trimming  off  a  proportionate  amount  of  the  surface  of 
the  model ;  otherwise  the  outer  surface  of  the  crown  will  be 
larger  than  is  desired.  When  the  plaster  model  for  the  crown 
is  made,  it  is  separated  from  the  rest  of  the  model  at  the  dotted 
line  seen  in  Fig.  206  and  trimmed  in  the  form  shown  by  the  cast 
A,  Fig.  207.  From  this  model  the  die  is  made  in  a  tube  with 
moldine  and  fusible  metal  as  described  at  page  104.  The  cast 
should  always  be  lengthened  at  the  neck,  so  that  the  crown 
when  constructed  shall  have  a  surplus  in  depth  of  gold  to  allow 
for  any  trimming  or  shaping  of  the  collar  that  may  be  required. 
The  counter-die  (B,  Fig.  207)  is  made  by  punching  a  hole  in 


Fig.  207. 


Fig.  208. 


Fig.  209. 


a  block  of  lead  and  hammering  the  die  into  it. 
The  crown,  which  is  usually  formed  of  pure  gold, 
^r^gold  slightly  alloyed,  or  gold  lined  with  very 
thin  platinum  from  XoT&!  to  No.  jlk  U.  S.  standard  gauge,  is 
then  made  by  first  stamping  a  piece  of  plate  (see  page  110)  in 
the  form  of  a  cap  of  gold  (A,  Fig.  208).  This  cap  is  then  placed 
on  the  cast  and  with  the  aid  of  the  counter-die  (B,  Fig.  207) 
iged  to  the  form  of  the  crown  B,  Fig.  208.  A  piece  of  kid 
leather  should  be  used  to  cover  and  protect  the  gold  from  the 
lend,  and  facilitate  its  removal  from  the  counter-die.  An  allow- 
ance for  the  thickness  of  the  leather  must  be  first  made,  by 
driving  it,  without  the  gold  <>n  the  cast,  into  the  counter-die  to 
enlarge  it  Ft'  this  i-  not  done,  the  gold  is  liable  to  be  torn  in 
the  swaging. 


®- 


THE  GOLD  SEAMLESS  CAP  CROWN.  1Q9 

Cuspid  crdwns  from  which  a  portion  of  the  gold  on  the  labial 
aspect  is  to  be  removed,  or  which  are  to  be  used  entire  as  a 
support  for  bridge-work,  can  usually  be  advantageously  formed 
with  a  seamless  cap  (Fig.  209).  The  necks  of  these  crowns  can 
be  contracted  in  fitting  in  a  contracting  plate,  or  slit,  lapped,  and 
soldered,  should  the  case  so  require.  (For  details  of  process  of 
adjustment  and  insertion,  see  "Process  of  Adjustment  of  Seam- 
less Contour  Crowns.") 


(D 


CHAPTER   X. 


-* 


GOLD   SEAMLESS   CONTOUR   CROWNS. 


The  artistic  requirement  of  all-gold  crown-work  is,  that  it 
shall  reproduce  the  anatomical  contour  of  the  natural  teeth. 
This  is  usually  accomplished  by  melting  solder  on  the  collar  and 
then  trimming  it  to  the  form  of  the  crown.  A  preferable 
method  is  to  shape  the  metal  forming  the  sides  of  the  crown  by 
swaging.  This  is  easily  done  in  a  crown  formed  in  sections,  but  a 
special  process  is  required  in  the  construction  of  seamless  crowns. 

A  contour  crown  can  be  made  by  placing  a  seamless  cap  on  a 
sectional  die  or  mandrel  of  the  shape  of  the  tooth,  first  swaging 


Fig.  210. 


Fig.  211. 


Fig.  212. 


TTf 


^HP~ 


the  grinding-surface  on  the  mandrel  and  then  stamping  downward 
on  the  straight  sides  of  the  crown  with  a  cap  fitted  to  the  shank 
pari  of  the  mandrel.  But  such  a  process,  like  many  others,  lb 
too  complicated  to  be  of  any  use  to  the  dental  practitioner.  The 
sectional  mold  method  here  presented  is  simple,  practical,  and 
general  in  its  application. 

To  describe  and  illustrate  the  process,  we  will  take  one  of 
the  mosl  difficull  crowns  to  construct, — a  superior  molar  (Fig. 
210).  A  natural  tooth,  or  one  made  of  plaster,  is  used  ae  a 
model.  From  this  a  sectional  mold  is  made,  as  illustrated  in 
1  ■"_  -.  i^ll  and  212,  in  Babbitt's   metal,  zinc,  or  fusible  alloy. 


D 


no 


rVucr>v.~   <L<AsLiJ*t+-     firu/WW 


* 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


Ill 


Into  the  mold  a  cap  of  gold  (Fig.  213)  23  to  24  carats  fine,  30  to 
32  gange,  is  adjusted,  fitting  tightly  the  orifice  of  the  closed 
mold.  The  mold  is  placed  in  a  vise,  the  cap  expanded  to  the 
general  form  of  the  mold  by  hammering  into  it  a  mass  of 
cotton,  and  then  swaged  more  in  detail  to  the  form,  and  with 
a  wood  point  or  a  burnisher  revolved  by  the  dental  engine 
burnished  into  every  part  of  the  mold  (Fig.  214).  To  facilitate 
the  process,  the  mold  should  be  frequently  opened,  and  the  gold 
annealed.  Fig.  215  represents  the  completed  crown.  These 
results  can  be  secured  by  other  styles  of  molds  :  Fig.  214  illus- 
trates one,  but  the  principle  is  the  same. 

Fig.  213.  Fig.  214.  Fig.  215. 

A 


^\ 


Another  method  is  to  form  a  fusible-metal  die  of  the  tooth  to 
be  crowned,  and,  after  having  stamped  the  grinding-surface  of 
the  crown,  to  reverse  and  swage  the  sides  close  to  the  die ;  the 
crown  is  then  relieved  of  the  core  (die)  by  heating  to  the  melting 
point  of  the  fusible  metal  and  pouring  it  out. 

For  practical  use,  a  variety  of  molds  skaald=&e  made  from 
natural  teeth  of  different  sizes  and  average  forms  to  serve  in 
corresponding  cases.  The  crowns  she«KL be  contracted  at  the 
neck  more  than  their  size  and  contour  call  for,  so  that  the  gold 
will  act  as  a  tight-fitting  band  which  will  expand  to  the  form  of 
the  root  as  the  crown  is  pressed  up  in  the  process  of  adjustment. 

Caps  of  metal  can  be  made  in  different  sizes  and  kept  on  hand 
for  use  in  this  and  other  styles  of  crown-work  by  means  of  a 
machine  (Fig.  216),  which  in  principle  is  such  as  is  used  by 
jewelers  for  forming  cap-shaped  pieces  of  gold,  and  in  factories 
for  making  copper  cartridges.  The  gold  plate,  cut  into  circular 
pieces,  is  pressed  through  a  steel  die-plate,  with  punches  gauged 
to  the  holes;  at  each  punch  a  small  portion  of  the  gold  is  turned 


112 


ARTIFICIAL  CROWN-  AND  BRIDGE-.WORK. 


over,  thus  preventing  its  lapping  or  creasing  (Fig.  217).    Repeated 
annealing  of  the  metal  is  very  necessary  in  this  process. 


Fig.  216. 


Methods  of  Contouring  Crowns  constructed  in  Sections. — In  con- 
structing a  crown  in  sections,  the  collar  can  be  first  formed  on  a 
Fig.  217.  Fig.  218. 


e      0     0   0 


\ 


mandrel,  then  placed  in  a  mold,  and  bur- 
Dished  to  the  shape  of  the  sides.  The  pro- 
cess of  its  adjustment  to  the  neck  of  the  root 
i-  then  continued  in  the  usual  manner. 

Another  method  is  to  stamp  or  burnish  np  the  collar  on  a  die 
representing  the  upper  sections  of  a  tooth,  designated  as  the 
middle  and  cervical  third  (Fig.  218).      After   contouring   the 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


113 


collar,  the  cap  is  adjusted  and  soldered  on.     With  a  metallic 
stamping  plate  (see  page  98)  these  caps  are  quickly  made. 

Process  of  Adjustment  of  Seamless  Contour  Crowns. — A  superior 
molar — one  of  the  most  difficult  teeth  to  operate  on — will  serve 
as  a  typical  case  to  illustrate  this  process.  The  crown  or  root  is 
first  shaped  and  if  necessary  built  down  with  amalgam,  straight, 
or  tapering  slightly  on  its  sides  toward  the  occluding:  surface, 
described   at   page   41.f"G-uided   by  tlie-^hape  of  the  natural 


teeth  and  measurements  by  calipers, — a  pair  of  tweezers  with 
a  screw  as  ^hown  in  Fig^/219  answers  the  purpose, — or  by  a 
plaster  model  of  the  mouth,  a  gold^efown  of  suitable  form  and 
size  is  selected.  The  crown  is-^flien  slipped  over  the  end  of  the 
prepared  natural  crown^orroot,  and  gently  pressed  and  worked 
straight  upward,  tl>e'g"old  at  the  neck  of  the  crown  expanding  to 
the  form  of  th,e^oot  until  the  edge  meets  the  margin  of  the  gum 
(A,  Fig>^220).  A  line  (B)  is  then  marked  on  the  gold  with  a 
sh>rJ>pointed  instrument,  parallel  to  the  margin  of  the  gum. 
The  crown  is  then  removed  and  the  edge  trimmed  off  to  this  mark 

Fig.  220. 


or  even  with  it  (A,  Fig.  221),  using  small  curved  scissors.  This 
process  should  be  repeated,  taking  off  a  little  at  a  time,  until  the 
edge  of  the  gold  meets  the  gum  evenly  at  all  points,  under  the 
free  edge  of  w-Men  it  is  then  pressed  up,'1md  if  the  occlusion 
is  correct  Durnisher  is  passed  around  the  cervical  portion  and 
the  gOm  burnished  accurately  to  the  root. 

Although  a  crown  can  usually  be  expanded  on  the  root  to  its 


114 


ARTIFICIAL  CROWS-  AXD  BRIDGE- WORK. 


Fig.  222. 


form  in  the  process  of  adjustment,  the  necks  of  natural  teeth 
vary  so  in  proportion  to  the  size  of  the  crown  that  it  often 
becomes  necessary  to  slightly  expand  the  gold  at  the  neck  of  a 
contour  crown.  This  is  quickly  and  easily  done,  without  alter- 
ing or  injuring  the  crown,  as  follows:  Soften  a  mass  of  gutta- 
percha, about  the  size  of  the  crown,  upon  the  closed  ends  of  a 

pair  of  clamp  forceps,  or  an  ap- 
pliance of  similar  construction. 
Introduce  the  gutta-percha  inside 
of  the  neck  of  the  crown,  which 
should  he  moistened  to  prevent 
its  adhesion.  Then  withdraw  the 
gutta-percha,  harden  it  in  cold 
water,  and  cut  through  the  center, 
between  the  points  of  the  forceps. 
The  points  of  the  forceps  armed 
with  the  gutta-percha  are  in  effect 
an  expanding  sectional  mandrel, 
and  by  reinserting  them  the  neck 
of  the  crown  may  be  expanded  in 
any  direction  according  to  the 
manner  in  which  the  forceps  and 
gutta-percha  have  been  inserted 
(Fig.  222).  A  gold  collar  can  be 
expanded  in  a  similar  manner. 

Before  the  crown  is  pressed  up 
to  its  apparently  proper  position, 
the  occlusion  should  be  examined 
and  calculations  carefully  made  to 
obviate  any  defects,  which  at  this 
stage  are  readily  corrected  by  proper  manipulation.  Any  desir- 
able change  can  usually  be  made  in  the  form  of  the  occluding  sur- 
face of  the  crown  while  on  the  tooth,  with  an  instrument  tapped 
by  the  mallet,  <»r  by  removing  the  crown,  holding  it  between 
the  thumb  and  fore-finger  with  the  second  finger  pressed  flat 
against  the  edge  of  the  cervical  portion,  and  tapping  the  gold  witli 
a  riveting  hammer.  The  position  can  be  changed  for  altering 
the  sides,  on  winch  the  flat   lace  of  tbe  hammer  should  be  used. 


GOLD  SHAM  LESS  COXTOUI!  CROWNS. 


115 


Strengthening  Seamkss  Gold  Contour  Crowns. — Additional 
strength  and  stiffness! can  be  given  to  seamless  gold  crowns 
when  desired,  in  several  ways.  The  liability  of  melting  the 
gold  which  forms  the  sides  of  the  crown  in  the  operation  has, 
with  some,  been  the  principal  objection  to  their  use.  ThisT 
]QWcverT  can  be  avoided  f\V  here  tAe  ensps  or  gnnding-snrfaccs^ 
reuuire  tilliiier^in  or  thickening,  which  is  done  from  the  inside, 
it 
parei 


mwever,  can  be  avoided  ^\y  here  Ifle  ensps  or  grinding 
squire  filling'm  or  thickening,  which  is  done  from  th 
t  is  safely  and  easily  accomplished  by  the  proper  usi 


gold 


proper  use  of  pre- 
?older  filings  (see  chapter  on  Plates  and  Solders, 
IV).  The  solder  in,  this  form,  U-r  tlie  dnvstate,  is  carried 
with  a  spoon-shaped  excavator,  and  packed  in  position  in  the 
cusps,  or  placed  on  any  desired  spot.  The  crown  is  then  held 
in  the  flame  of  a  small  alcohol  lamp  and  headed  sufficiently  to 
fuse  the  solder,  vv^hich  will  melt/d^wn  exactly  where  it  is  put, 
and  not  flow  over  the  adjacent  surface.  During  the  process  the 
crown  should  be  helcl  by  grasrtfhg  the  edge  oflone  side  of  the 
collar  with  the  points  of  a  pajnof  tweezers,  in  §uch  a  position 
that  a  full  view  of  the  inajde  /Sujrface  shall  be  presented,  and  the 
melting  of  the  solder  thus^  determined  instantly.  Should  the 
sides  of  the  crown  require  strengthening,  a  small  portion  of  the 
prepared  solder  filings  caivoe  mpistened,  and  with  k  small  camel's- 
hair  artist's  brush  painted  over^the  inside  surface.  When  suffi- 
cient heat  is  applied,  the  solden  wtU  be  fused  evenw  over  the  gold 
without  the  slightest  .risk  of  meltiW  the  sidesvor  changing  the 
general  form  of  the  interior  offthe  crWn.  Whenijboth  the  cusps 
and  the  sides  of  the. brown  are  to  be  strengthened,  tfli^sides  should 
be  done  first.  Another  metl  od  is :  Take  a  pellpt  of  moldine, 
moisten  it  with  water,  and  wo]  k  it  until  quite  soft  J  then  rqll  it  out 
lengthwise,  an&envelop  the  i  rown  on  its  sides  v  ith  a  very  thin 
continuous  piece,  leaving  exposed  the  parts  oi\th€  occluding -sur- 
face that  are  to  be  filled  in.  Pass  around  on  the  outside  of  the 
moldine,  without  touching  tl  e  crown,  a  fine  wTir  l  and  twrist  the 
ends  together  for  a  handle  (F:g.  223).  Grind  some  borax  mixed 
with  water  to  a  cream-like\ccnsistence,  and  with  a  small  pellet 
of  cotton  twisted  on  an  instrument  paint  the  inside  of  the  crown 
with  the  borax  just  where  yo$\wish  the  solder  tp  flow.  Then 
place  inside  the  cusps  an  easy^flowing  solder  than  has  been  cut 
very   fine   and  immersed  in   the\x>rax.     Hold   the  crown   in 


116 


ARTIFICIAL  CROWX-  AXD  BRIDGE- WORK. 


the  flame  of  an  alcohol  lamp  or  in  a  blue  gas  flame,  and  heat 
slowiy-sothat  the  position  of  the  solder  shall  not  he  changed  by 
the  fusing  ofHlie  borax.  Increase  the  heat  until  the  solder  flows 
over  the  surface>sf  the  gold,  which  itMoes  very  quickly  when 
the  melting-point  is  reached.  Then  the  croVn  must  be  instantlv 
removed  and  examined.  T^ufficient  solder — the  tilings  previous!}' 
referred  to  are  safer  for  this  purpose  than  solder  cut  in  pieces-^ 
should  be  placed  in  the  crown  to  give  it  the  desired  sbRtmgth  in 
one  heating,  but  in  case  of  necessity  more  can  be  added  and  the 
process  cautiously  repeated.  The  moldiue  protects  the  sides,, 
which  generally  take  up  the  greatest  degree  of  heat.  r     ._ 

—  TTiTIQ  seamless  crowns  can  also  be  strengthened  or  filled  with 
solder  or  even  18-  or  20-carat  gold  plate,  by  investing  the  outside 


Fig.  223. 


Fig.  224. 


Fig.  225. 


surface  of  the  crown  in  plaster  and  marble-dust  (Fig.  224),  and 
then  with  a  small  flame  of  the  carbo-oxyhydrogen  blow-pipe, 
not  over  one-half  an  inch  in  length,  introduced  inside  of  the 
crown,  melt  and  flow  the  solder  or  gold  plate  over  any  portion 
or  even  all  of  the  surface  of  the  gold.  The  crown,  if  formed 
of  gold  with  a  thin  lining  of  platinum,  can  be  soldered  by  either 

lethod  with  little  danger  of  being  melted.  - 

If  for  some  special  purpose  it  is  desirable  to  strengthen  the 
neck  of  a  crown  by  increasing  the  thickness  of  tbe  gold  on  the 
externfld  surface,  the  crown/is  first  soldered  ty  stiffen  the  occluding 

-Ul'tiiee     as     above     1 1  e-.cn  I  >e<  1 .        TilC    insi(JV()f   the     d'OWn     is     tliell 

filled  nolid   with   naoldine  or  investing  materia}*     The  gold   \»J^ 

M>ed  around  the  crown,  along  the  line  of  the  cervical  c>\>j;<- 
(A,  Fig.  225),  only  as  low  as  the  stiffening  is  required,'  Along 
this    part   borax    i-    applied    with   a    brash,  and    -mall    pieces   of 


aaV 


GOLD  SEAMLESS  CONTOUR  CROWNS. 


117 


Fig.  226. 


20-carat  solder  placed  and  melted  in  succession,  the  crowu^being 
tunietPdtHdn^r  thr  pro<es>*mtil  the  neck  is  entirely  encircled.  A 
very  finenlafcrfTum  wire  or  a  narrow  strip  of  platinum  foil  adapted 
"on  tlu'  outside  olShc  crown,  at  the.  point  soldered,  lessens 
lie  quantity  of  solder  required  and  facilitates  the  operation. 

Supporting  the  Crown. — In  crowning  teeth  with  living  pulps 
there  is  sufficient  of  the  natural  crown  present  to  afford  a  secure 
foundation  and  attachment  for  the  artificial  crown,  as  is  also  the 
case  with  many  teeth  that  are  pulpless;  but  in  badly  broken- 
down  crowns,  or  where  only  the  root  is  present,  a  metallic  pin 
or  post  should  be  inserted  in  the  root,  and  the  part 
built  down  with  amalgam  to  a  form  which  will  afford 
secure  support  and  attachment  to  the  artificial  crown, 
and  facilitate  its  adjustment.  (See  "  Special  Prepa- 
ration of  Badly-Decayed  Teeth  or  Roots,"  page  42.) 

In  many  cases  the  required  support  for  the  crown 
.can  be__sejnired  by  means  of  a  screw  (Fig.  226). 
How  screw\|is  inserted  in  the  root-canal  A  (see 
page  55).  Amalgam  is  then  packed  in  the  lower 
section  of  the  artificial  crown,  C,  to  the  line  B,  and 
into  the  amalgam  the  screw  is  pressed.  Amalgam  which  has 
been  put  in  a  piece  of  chamois  and  the  mercury  pressed  out 
with  a  pair  of  pliers  until  it  is  in  the  condition  termed  "  dry  " 
will  adhere  to  the  gold  without  affecting  it.  The  amalgam  is 
first  placed  in  the  crown  slightly  in  excess  of  the  amount  re- 
quired, and  the  crown  adjusted,  removed,  and  the  surplus 
scraped  out.  This  process  is  continued  until  the  screw  or  the 
crown  section  of  the  natural  tooth  forms  an  indentation  in  the 
amalgam,  which  it  will  fit  when  the  crown  is  cemented  on.  The 
vent  for  the  escape  of  air  and  surplus  cement — which  should 
always  be  put  in  perfect-fitting  crowns  and  afterwards  filled  with 
gold  or  amalgam — should  be  in  the  line  of  the  indentation  in 
the  amalgam,  with  which  it  must  connect  (D).  (For  process  of 
cementation,  see  article  on  "  Insertion  and  Cementation.") 

These  crowns  can  be  inserted  in  an  easy  and  inexpensive  man- 
ner by  fillino-  in  the  lower  section  of  the  crown  with  amalgam 
instead  of  gold,  and  allowing  the  head  of  the  screw  or  the  nat- 
ural crown  to  indent  the  amalgam  as  above  described,  and  then 


118 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


cementing   on   the   crown   with    oxyphosphate    in    the    usual 
manner. 

In  a  case  so  inserted,  with  no  antagonizing  teeth,  the  result  is 
the  same  as  though  the  inside  of  the  occluding  surface  of  the 
crown  was  filled  with  gold ;  but  if  antagonizing  teeth  are  present, 
the  gold  of  the  crown  is  apt  to  wear  through  in  places  and  expose 
the  amalgam. 

— ff~a  tooth  is  short  and  the  articulation  such  as  to  require  the — 
reduction  of  the  collar  to  a  size  which  will  suggest  insecurity 
when   the   crown  is   cemented,  or  if  the    tooth    is   pulpless,  a 
headed  or  barbed  pin  that  will  anchor  in  the  root  should 
be  soldered  in  the  interior  of  the  crown,  as  shown  in 
Fig.  227.     This  is  done  by  passing  the  pin  through  a  \ 
hole  made  in  the  occluding  surface  of  the  crown,  adiust- 
ing  the  crown  in  the  mouttu  removing, "m^esting,  and 
soldering  the  pin  from  the  outside  surface  of  the  crown — 
ic  advantages  of  seamless  contour  crowns  are,  that  they 
represent  perfectly  the  tooth  in  its  anatomical  contour,  present  a 
uniform  surface  of  pure  gold,  which  preserves  its  color  without 
tarnishing,  and  are  quickly  and  easily  adjusted.     Their  defects 
are  inability  to  meet  the  requirements   of  abnormally-shaped 
roots  and  anomalous  articulations. 


Fig.  227. 


CHAPTER  XI. 

GOLD  CROWNS  WITH  PORCELAIN  FRONTS  FOR  TEETH  WITH 
LIVING  PULPS— COLLAR  CROWNS  HYGIENICALLY  CON- 
SIDERED. 

In  the  anterior  teeth,  in  case  of  atrophy  or  erosion,  or  where 
decay  has  destroyed  the  appro  ximal  sides  of  a  tooth  in  such  a 
manner  that  crowning  is  considered  the  most  desirable  operation 
to  perform,  the  pulp  is  frequently  found  unexposed  and  in  a 
normal  condition.  The  importance  of  its  preservation  in  such  a 
case  is  unquestionable. 

The  methods  at  present  most  commonly  used  to  form  a  crown 
under  such  conditions  are  in  many  respects  defective  and 
objectionable,  notwithstanding  the  advantages  their  iudorsers 
claim  for  them. 

In  the  first  place,  all  crowns  of  platinum  or  iridio-platinum 
with  body  baked  on  to  raproflpint  the  labial  aspect  of  the  toftth/^wZ^LA 
have  a  dead  and  unnatural  appearance,  and  finnan  those  on  which 
films  of  porcelain  representing  teeth  are  baked  the  porcelain 
frequently  chips  off,  and  both  styles  usually  protrude  beyond 
the  line  of  the  adjoining  teeth- 

The  method£_here  presented  i^  intended  to  overcome  these 
objections  and  to  produce  a  more  satisfactory  result,     The  de- 

-vscriptive  details  of  the  crowning  of  a  central  incisor  will  serve  to 

illustrate  fy  A  model  is  first  made  representing  the  tooth  in  a 
perfect  form.  This  can  be  done  either  by  shaping  the  natural 
tooth  in  the  mouth  with  oxyphosphate  or  gutta-percha,  taking 
an  impression  of  it  in  wax  or  moldine,  and  forming  a  model 
in  plaster  or  fusible  alloy,  or  by  taking  a  natural  tooth  and 
shaping  it  to  correspond,  or,  if  the  operator  is  an  expert,  carving 
one  from  a  piece  of  plaster. 

119 


120 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


Two  easts,  one  of  the  coronal  form  of  the  tooth  (Fig.  228), 
and  the  other  of  only  the  palatal  and  approximal  portions  (Fig. 
229,  arc  made,  using  the  moldine  in  tubes  with  fusible  metal. 
This  will  consume  only  a  few  minutes.  A  piece  of  gold  and 
platinum  crown  plate,  No.  34  U.  S.  standard  gauge,  about  the 
length  and  circumference  of  the  tooth,  is  then  struck  up  on  the 
palato-approximal  cast,  from  which  it  receives  the  palatal  and 
approximal  aspects  of  the  tooth  (Fig.  230).  It  is  then  transferred 
to  the  coronal  cast,  which  is  previously  trimmed  the  thickness 
of  the  gold  plate  upon  the  approximal  surfaces,  and  worked 
down  to  the  exact  form  of  the  tooth  on  the  anterior  portion. 
The  metal,  which  is  then  the  exact  form  of  the  tooth  on  all 
sides,  is  cut  even  at  the  incisive  edge,  the  seam  down  the  front 


Fig.  228. 


Fig.  229. 


Fig.  230.        Fig.  231. 


Fig.  232. 


Fig.  233. 


beveled,  lapped,  and  marked,  then  slightly  opened,  and  the  gold 
slipped  off  the  die.  Guided  by  the  mark,  the  gold  is  then 
pressed  back  to  the  form  assumed  on  the  die,  and  fitted  to  the 
natural  crown,  which  should  have  been  previously  trimmed  and 
shaped  as  described  on  page  41  (Fig.  20),  and  the  joint  on  the 
labial  side  soldered  (Fig.  231).  Into  the  incisive  edge,  which  is 
open,  ;i  narrow  strip  of  gold,  about  one-sixteenth  of  an  inch  in 
width  and  thick  enough  to  till  the  space,  is  fitted  and  soldered. 
Thi>  strengthens  the  whole  crown,  and  forms  a  protecting  edge 
tor  tin-  porcelain  front. 

We  have  dow  a  gold  contour  crown,  an  exact  imitation  of 
the  tooth  under  treatment.  The  crown  is  then  filled  with 
plaster,  and  the  labial  portion  ground  and  tiled  away,  so  as  to 
leave  the  Upper  part  to  form  the  band,  and  the  1<>\\  er  the  incisive 
edge,  a-  represented  in  Fig.  232. 


GOLD  CROWNS   WITH  PORCELAIN  FRONTS.  \2\ 

A  porcelain  tooth  which  matches  in  shade  and  form  is  then 
ground  and  thinned  down — in  which  operation  the  pins  are 
removed — to  the  form  of  a  thin  porcelain  front,  thickest  at  the 
incisive  edge.  This  front  is  fitted  to  replace  and  represent  the 
labial  portion.  The  porcelain  is  then  removed  and  a  piece  of 
platinum  foil  adapted  to  its  back,  and  turned  just  barely  over 
the  edges,  the  upper  and  lower  of  which  should  be  slightly 
tapered  off,  as  shown  in  Fig.  233. 

The  platinum  can  be  made  to  fit  closely  to  the  porcelain  by 
rubbing  the  edges  on  a  piece  of  cloth  or  chamois,  on  a  flat 
surface.  The  porcelain  front  is  then  adjusted  on  the  crown 
and  cemented  on  one  side  with  wax,  and  the  crown  invested  in 
plaster  and  marble-dust,  so  that  the  seam  along  the  edge  of  the 
platinum  and  gold  is  exposed  on  the  cemented  side  and  at  one 
a-  shown  iu  Fig.  -;34.  When  the  investment  has  set,  the 
wax  is  removed,  and  |Wfc pored  gold  solder  filings,  26  oaimtfino,  are 
packed  in  and  over  the  seam,  in  quantity  sufficient  to  make  a 

Fig.  234.  Fig.  235.  Fig.  236.  Fig.  237. 


perfect  joint  when  finished.  The  investment  is  then  uniformly 
heated  and  the  seam  soldered.  Care  must  be  taken  not  to  flow 
the  solder  upon  the  porcelain,  or  to  use  more  borax  than  is 
absolutely  necessary,  as  otherwise  the  porcelain  will  be  fractured. 

"When  the  investment  is  cold,  the  crown  is  removed,  again 
invested,  and  the  remainder  of  the  seam  soldered,  or  the  invest- 
ment can  be  immediately  removed  from  the  other  side,  and  the 
soldering  completed;  though  this  latter  plan  is  attended  with 
some  risk  to  the  porcelain. 

After  the  crown  has  gone  through  the  finishing  process,  the 
excess  of  porcelain  on  the  inside  of  the  crown  is  ground  away 
in  a  few  minutes  with  a  small  piece  of  corundum  melted  on  an 
old  oval-shaped  bur.  The  cavity  in  the  crown  is,  meanwhile, 
kept  filled  with  water  (Fig.. 235). 


7 


122 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORL 


(Tl-u 


vt~ 


kj~un*r**^ 


Fig.  238. 


In  adjusting  the  crown,  the  natural  tooth  ann  he  smeared  with 
articulating  pastef  which  will  easily  mdica'tijlany  point  obstructing 
its  perfect  adaptation.     When  fitted,  the  crown  is  attached  with 
hosphate  cement.     Fig.  236  shows  the  completed  crown. 
Bicuspids  and  molars  can  be  made  in  the  same  manner  by 
using  a  contour  crown  of  gold  lined  with  platinum  (see  chapter 
on  contoured  crowns),  and,  after  its  adjustment,  fill- 
ing in  the  crown  with  plaster,  and  then  cutting  away 
the  hrbiajDortlon  and  replacing  it  with  porcelain 
(Fig.  237). 

Crowning  in  Cases  of  Abrasion. — In  a  case  of  ex- 
tensive abrasion  of  the  incisive  edges  of  the  anterior 
teeth,  with  pulp  living  though  considerably  calcified 
in  the  coronal  section,  crown-work  to  restore  the 
length  and  form  of  the  teeth  is  best  performed  by 
removing  a  portion  of  the  labial  aspect  of  the  natural 
crown  and  then  forming  the  artificial  crown  similar 
to  a  gold  collar  crown  without  the  pin.  An  accurately  adapted 
collar,  cemented  with  oxyphosphate,  will  usually  hold  the  crown 
securely.  Fig.  238  gives  an  outline  of  the  construction  of  such 
a  crown.  If  a  case  should  suggest  the  necessity  of  a  pin,  a  short 
one  can  be  so  inserted  as  not  to  endanger  the  pulp. 

COLLAR    CROWNS    HYGIENICALLY    CONSIDERED. 

The  principal  argument  against  ferruled  or  collared  crowns  is 
that  they  are  productive  of  irritation  to  the  peridental  mem- 
brane, ultimately  causing  its  absorption  and  the  exposure  of  the 
collar.  This  would  be  theoretical \y  and  practically  true  of  a 
rough  or  porous  substance  encircling  the  root,  or  of  an  imper- 
fectly and  unskillfully  adjusted/ferrule  or  collar. which  would  by 
its  presence  hold  a  position  analogous  to  a  calcareous  deposit,  but 
DO  such  comparison  can  he  fairly  made  with  a  perfectly  fitted 
collar,  forming  at  its  edge  a  smooth  and  imperceptible  union 
with  the  .-ides  of  the  root,  and  presenting  a  uniform  and  benign 
surface  to  the  investing  membrane.  In  case  of  perfectly  adapted 
collars,  when  any  irritation  of  the  membrane  exists,  it  will  be 
found  to  result  from  such  causes  as  usually  produce  it  when  the 
natural   crow  m-    are    present,   namely,  dental   concretions.      A 


COLL  A  R  CRO  WNS  HYGIENIC  A  LL  Y  CONSIDERED.  \  03 

tarnished  and  unclean  condition  of  the  surface  of  the  gold  of  the 
collar  will  produce  an  irritation  of  the  membranes,  which  is  a 
matter  independent  of  the  collar  itself,  and  easily  remedied  by 
cleansing  and  polishing  the  surface.  Where  an  acid  condition 
of  the  secretions  of  the  mouth  exists,  a  collar  of  platinum  or 
iridium,  or  one  of  gold  and  platinum  crown-metal,  presenting 
tlw  platinum  surface,  is  suggested  in  preference  to  gold,  as 
these  metals  will  not  be  affected,  but  will  constantly  present 
an  untarnished  surface. 


jA^trYT^&v  aM^^cr^K-^o   <£v^Wjr*~      £c&jtsr- 


CHAPTER  XII. 


SPECIAL  FORMS  OF  GOLD  CROWNS  WITH  PORCELAIN  FRONTS. 


THE   PARR    CROWN. 

This  crown,  which  in  form  of  construction  possesses  special 
points  of  merit,  is  largely  used  by  Dr.  H.  A.  Parr. 

The  root  is  prepared,  banded,  and  capped  without  a  pin,  the 
same  as  for  a  gold  collar  crown  (A,  Fig.  239).  A  hole  is  made 
in  the  cap,  and  a  post  fitted  in  the  canal.  A  piece  of  gold  plate, 
fully  the  size  of  the  cap  on  the  root,  is  adjusted  on  the  post 
above  the  cap  by  making  a  hole  in  the  gold  in  whieh  the  post 
will  fit  tightly.    The  gold  plate  is  then  adapted  to  the  cap  on  the 


Fig.  2?,9. 


Fig.  240. 


Fig  241. 


root,  and  burnished  into  any  open  space  around  the  post, 

forming  an  outside  cap;  the  pin  and  the  outer  cap  are 

then  removed  and  soldered  together  and  adjusted  on 

th«;  inner  cap,  and  the  edge' of  the  outer  cap  trimmed  even  with 

it  (B).     The   porcelain  tooth  to  form  the  crown,  C,  is  fitted  and 

attached  to  the  outer  cap,  which,  when  finished,  is  cement<d 

in  position  as  shown  in  Fig.  240. 

The   advantage    of  this   form    of  crown  is  that  the  root  is 

irely  and  permanently  capped  independently  of  the  crown, 
which  can  be  removed  without   disturbing  the  cap  on  the  root. 

i  i't 


THE  LEECH  CROWS. 


125 


Fio.  242. 


Dr.  Parr,  in  using  this  stylo  of  crown  in  bridge-work,  constructs 
the  outer  cap  with  a  band  which  half  encircles  the  inner  cap, 
and  tapers  oft  from  the  palatal  to  the  labial  section,  as  illustrated 
in  Fig.  241.  The  cap  on  the  root  is  cemented  with  oxyphos- 
phate.  and  the  post  and  outer  cap  with  gutta-percha. 

THE    LEECH    CROWN. 

Dr.  Leech's  crown  is  thus  described  by  Dr.  J.  E.  Dexter : x 
"A  method  devised  by  Dr.  H.  K.  Leech,  of  Philadelphia, 
shown  in  Fig.  242,  and  described  in  the  Dental  Cosmos  for  April, 
1879,  is  as  follows  :  The  root  is  drilled  out  to  a  depth  of  about 
three-eighths  of  an  inch  to  a  diameter 
of  about  No.  16,  standard  (American) 
wire  gauge,  the  bottom  of  the  hole 
being  flared  or  enlarged,  and  the 
canal  above  filled  with  gutta-percha. 
A  gold  tube  is  made  to  fit  the  hole 
accurately  and  project  sufficiently  for 
convenience  of  handling,  and  is  sol- 
dered through  a  hole  in  a  gold  base 
struck  to  the  root,  projecting  through 
the  plate  some  distance.  A  plate 
tooth  is  fitted  to  the  root  and  plate  and  soldered  to  the  latter, 
gold  being  flowed  onto  the  plate  and  backing  and  around  the 
projecting  tube  to  form  the  palatal  contour,  and  the  tube  cut  off 
flush  with  the  latter.  We  now  have  a  plate  tooth,  gold  backed, 
with  a  tube-pivot,  the  orifice  of  which  opens  on  the  palatal 
aspect  of  our  tooth.  The  root-end  of  the  tube  is  now  slit  per- 
pendicularly in  three  or  four  places,  for  about  two-thirds  of  its 
length,  a  thin  sheet  of  warmed  gutta-percha  is  placed  on  the 
base  of  the  crown  around  the  tube,  and  the  whole  is  pushed 
securely  to  place.  Xow  pack  gold  or  tin  into  the  tube,  condensing 
the  bottom  portions  so  that  the  slit  end  mill  spread  and  tightly  fill  the 
dared  end  of  the  hole  in  the  root,  and  the  operation  is  complete." 

A  collar  crown  fastened  with  a  tube-pivot  as  described  can  be 
used  to  advantage  in  detachable  bridge-work,  as  the  tube  if 
filled  with  tin  foil  will  admit  of  the  crown  being  easily  detached. 


1  Dental  Cosmos,  May,  1883. 


126 


ARTIFICIAL  CROUX-  AXD  BRIDGE- WORK. 


THE    LOW    CROWN. 


In  the  method  for  crowning  pulpless  roots  of  Dr.  J.  E.  Low, 
of  Chicago,  the  root-canal  is  reamed  out  with  an  instrument 
which  at  the  same  time  shapes  the  end  of  the  root,  or  a  portion 
of  it,  to  receive  a  combined  post  and  cap,  which  the  inventor 


Fig.  243. 


calls  a  "step-plug,"  from  its  peculiar  form.  There  are  seven 
sizes  of  the  cutting  instruments  (Fig.  243),  and  corresponding 
exactly  with  them  seven  sizes  of  the  step-plugs.  These  step- 
plugs  are  not  unlike  a  minute  cone-pulley  set  in  a  saucer-shaped 
cap  upon  the  bottom  of  which  is  a  stout  boss.  They  are  made 
of  platinum  and  nickel.     As  these  last  fit  the  prepared  root 

accurately,   it  is   claimed   that   they 
Fl°-246-     afford  a  secure   foundation    for   the 

4  artificial  crown  and  also  prevent 
longitudinal  fracture  of  the  root. 
To  describe  and  illustrate  the  pro- 
cess, the  root  of  a  central  incisor  (Fig. 
244)  is  selected.  The  end  of  the 
root  is  first  ground  level  with  the  palatal  margin  of  the  gum.  A 
cutting  instrument  of  suitable  size  is  then  selected,  with  which 
the  root  is  shaped  as  shown  in  Fig.  245.  The  end  of  the  root  is 
removed  enough  to  permit  the  palatal  edge  of  the  cap  of  the  step- 
plug  (Pig.  246),  which  is  then  adjusted,  to  pass  just  below  the 


THE  LOW  CROWN. 


127 


margin  of  the  gum.     Fig.  247  shows  the  step-plug  imposition, 

and  ready  for  the  adjustment  of  the  porcelain  front  (Fig.  248)  and 
ilir  construction  of  the  crown,  which  is  completed  as  in  methods 
previously  described.  The  porcelain  front  when  adapted  should 
meet  the  labial  margin  of  the  gum,  the  labial  surface  of  the  end 
of  the  root  being  trimmed  (with  the  cap  in  position)  with  a 
corundum  wheel  when  necessary  to  permit  it.  When  the 
porcekrn  front  is  to  be  adjusted  in  the  mouth,  the  backing 
should  be  warmed,  a  small  quantity  of  resin  and  wax  cemented 
upon  it,  the  tooth  placed  in  position  in  the  mouth,  and  the  con- 
vex surface  of  the  step-plug  cap  carefully  imbedded  in  the  wax. 
The  wax  and  the  porcelain  front  should  next  be  carefully  removed 


Fig.  247. 


Fig.  249. 


Fig.  250. 


Fig.  252. 


Fig.  254. 


Fig.  253. 


Fig.  255. 


Fig.  248. 


and  then  the  step-plug,  using  pliers  for  the  last.  The  step-plug 
is  then  placed  in  the  wax  impression,  to  which  it  is  fixed  with  a 
heated  spatula,  and  invested  for  soldering.  Fig.  249  shows  the 
completed  crown  ready  for  final  adjustment,  and  Fig.  250  gives 
a  sectional  view  of  it  in  position. 

In  crowning  bicuspid  roots,  one  step-plug  in  the  palatal  side  of 
the  root  (Fig.  251)  is  usually  sufficient,  the  remaining  exposed 
surface  of  the  root-end  being  covered  by  adapting  thin  platinum 
plate  over  it  and  onto  the  surface  of  the  cap  before  adjusting 
the  porcelain  front  (Figs.  252  and  253).  Figs.  254  and  255  show 
the  completed  bicuspid  crown  before  and  after  the  final  adjust- 
ment.   Molar  roots  are  capped  similarly,  using  two  step-plugs. 

The  plugs  are  useful  in  building  up  badly-decayed  roots  to 
support  and  retain  all-gold  crowns. 


128 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig,  256. 


THE   PERRY  CROWN. 

Dr.  Safford  G.  Perry,  of  New  York,  employs  a  porcelain 
crown  in  combination  with  a  capped  root.  A  bicuspid  will  be 
taken  as  a  typical  case  to  illustrate  Dr.  Perry's  method.  The 
end  of  the  rout,  by  trimming  the  edge,  is  given  the  tapering 
form  shown  at  A,  Fig.  256.  The  collar  (B^ 
is  made  very  narrow.  A  cap  is  fitted  on 
the  collar,  and  a  post  or  posts  fitted  in  the 
roots  and  through  the  cap.  The  entire 
cap  is  made  of  platinum  soldered  with 
pure  gold.  Enough  of  the  post  is  allowed 
to  extend  beyond  the  cap  to  attach  and 
firmly  retain  the  porcelain  crown  (C). 
One  or  two  holes  to  serve  as  vents  are 
drilled  through  the  top  of  the  cap,  and  it  is  set  in  place  with 
oxyphosphate,the  excess  escaping  through  the  holes.  The  holes 
are  then  reamed  out  and  filled  with  gold,  and  the  edge  of  the 
collar,  under  the  gum,  is  burnished  to  the  root.  The  porcelain 
crown  used  is  similar  in  principle  to  the  Howland  crown,  but 
differs  in  the  details  of  its  formation.  The  base  is  given  a  curve 
approximating  that  of  the  line  of  the  margin  of  the  gum,  with 
the  palatal  portion  projecting  slightly  above  it,  to  include  a  little 
of  the  cervix.  The  cavity  in  the 
porcelain  is  given  a  size,  form, 
and  position  which  will  receive 
the  posts  extending  from  the  cap 
without  impairing  the  strength 
of  the  crown-walls.  Thus  they 
an-  made  round  in  the  incisors 
and  cuspids  (A,  Fig.  257),  oval  in 
tin-  bicuspids  (A,  Fig.  258),  and  following  the  curve  of  the  line 
<»t  the  posts  in  the  molars.1 

1  The  form  of  porcelain  crown  'Inscribed  is  also  used  by  Dr.  Perry  without 
capping  the  root,  similarly  to  the  Howland  crown.  In  .such  cases  he  usually 
the  end  of  the  toot  either  with  u  surface  of  < "ndensed  gold  foil  anchored 
in  a  reamed  cavity  formed  ;m.iiri<l  the  post  in  the  root-canal,  or  with  a  very  thin 
disk  of  gutta-pcnha.  The  di.~k  with  the  aid  of  heat  or  chloroform  is  made  to 
form  a  line  of  onion  between  the  root  and  crown.  In  both  methods  oxyphos- 
Ll  cued  in  i  he  cavity  which  receives  the  post  to  attach  the  crown. 


Fig.  257 


Fig.  258. 


THE  PERR Y  CROW 'N.  129 

A  suitable  crown  (C,  Fig.  256)  having  been  selected,  it  is  ground 
and  fitted  in  proper  position  on  the  cap.  This  operation  is  facili- 
tated by  perforating  a  disk  of  marking-paper  with  the  posts  and 
adjusting  it  on  the  cap.  Then,  as  the  crown  is  placed  on  the  cap 
and  pressed  against  it,  points  which  prevent  perfect  adjustment 
are  marked  on  the  porcelain.  By  this  means  a  close  joint  is 
easily  secured.  The  edge  of  the  porcelain  should  be  fitted  under 
the  free  margin  of  the  gum,  especially  at  the  cervico-palatal 
part.  The  porcelain  crown  is  next  set  over  the  projecting  pins, 
and  cemented  to  the  cap  with  oxyphosphate. 

The  advantage  of  this  method  is,  that  the  root  being  slightly 
tapered,  the  collar  can  be  made  to  fit  absolutely,  while  the 
excess  of  oxj'phosphate  is  gotten  rid  of  through  the  vent-holes, 
instead  of  being  squeezed  out  around  the  edge  of  the  collar. 
The  edge  of  the  collar  being  made  to  a  knife-edge,  can  be 
properly  burnished  before  the  crown  is  placed,  so  that  it  will  not 
irritate  the  gum  or  make  a  shelf.  The  crown  covers  the  cap, 
and  can  usually  be  ground  and  fitted  so  as  to  entirely  hide  any 
exposed  portion  of  the  collar,  the  junction  of  which  with  the  cap 
should  be  trimmed  and  then  rounded  with  a  burnisher,  to  give  a 
form  which  will  better  meet  the  interior  of  the  porcelain  cap  or 
crown.  Fig.  258  shows  the  finished  crown.  Fig.  257  gives  a 
sectional  view  of  a  central  incisor.  The  porcelain  can  be 
replaced  at  any  time  in  case  of  fracture  without  disturbing  the 
cap  on  the  root.  The  easy  repair  thus  afforded,  the  simplicity 
of  construction,  and  the  artistic  result,  are  the  special  features  of 
this  form  of  crown. 


CHAPTER  XIII. 


CROWNING  FRACTURED  TEETH  AND  ROOTS— CROWNING. 
MOLAR  ROOTS  DECAYED  APART  AT  BIFURCATION— CROWN- 
ING IN  CASES  OF  IRREGULARITY. 

The  crowning  of  fractured  teeth  and  roots  is  a  process  that 
requires  skill  and  delicate  treatment.  Its  practicability  depends 
on  the  nature  of  the  fracture,  the  previous  health  of  the  parts, 
and  the  length  of  time  that  has  elapsed  since  the  occurrence 
of  the  injury. 

LONGITUDINAL   FRACTURE   OF   THE   CROWN    AND   ROOT. 

By  this  is  meant  a  fracture  extending  lengthwise  through 
the  crown  or  what  remains  of  it,  and  down  the  root  or  roots. 
Foreign  substances  having  been  removed  from  within  and  around 
the  parts,  the  crevice  of  the  fracture  is  syringed  thoroughly 
with  a  solution  of  carbolic  acid  and  tepid  water.  The  fractured 
Pio.  259.  parts  of  the  root  are  then  drawn  together  with  waxed  floss 
silk,  passed  at  least  twice  around  the  tooth,  and  tied,  the 
ends  being  passed  through  twice  in  forming  the  knot. 
The  pulp-chamber  is  then  prepared,  and  dovetail  slots 
drilled  across  the  parts  (Fig.  259).  [f  it  is  suspected  thai  in  the 
preparation  any  particle-  of  dentine  have  invaded  the  crevice 
ofjthe  t'raeture^the  ligature  juust_.be  removed,  the  parts  again 
Byringed,  ami  the  ligature  reailjustedy  The  upper  pails  of  the 
root-canal-  are  then  filled  with  gutta-percha,  and  the  main  body 
of  the-  cavity  ami  the  -lots  with  a  hard,  quick-Setting  amalgam. 
A  collar  crown  should  always  he  used  in  these  cases.  If  the 
form  to  he  need  ha-  a  post,  a  -hurt,  .-mall  tuhe  of  gold  or 
platinum  should  he  -.t  in  the  amalgam  in  proper  position  to 
ive  it.  At  the  next  visit  of  the  patient  the  ligature  is  removed 
and  the  parts  carefully  prepared  for  crowning.  The  circum- 
130 


CROWNING  FRACTURED  TEETH  AND  ROOTS.  131 

ference  of  me  root  is  first  measured  vvitli  a  wire,  a  tight-fitting 
collar  constructed,  and  the  crown  then  completed  in  the  usual 
manner. 

The  great  drawback  in  these  cases  is  that  the  patient  generally 
fails  to  present  himself  immediately  for  treatment,  and  foreign 
substances  work  into  the  fracture,  causing  inflammation,  which 
is  difficult  to  control.  Often  subsequent  to  treatment  a  septic 
condition  of  the  fracture  supervenes,  the  irritation  caused  thereby 
and  the  exudations  from  the  fracture  becoming  so  annoying  thai 
extraction  is  the  only  alternative. 

Teeth  fractured  as  above  described  are  rarely  found  with  living 
pulps.  . 


FRACTURE   OF   THE   CROWN    WITH    SLANTING   FRACTURE   OF 

THE   ROOT. 

fractures  of  this  kind  are  common,  especially  in  bicuspids, 
where  large  fillings  are  inserted  extending  from  the  anterior  to 
the  posterior  approximal  walls,  leaving  the  separated  buccal  and 
palatal  cusps  to  bear  the  brunt  of  mastication. 

In  such  cases  the  fracture  seldom  extends  beyond  the  edge  oi 
the  alveolar  process.     The  fractured  part  having  been  carefully 

Fig.  260.  Fig.  261. 


removed,  a  dovetail  slot  is  made  in  the  crown  or  root,  into 
which  gutta-percha  is  inserted  for  a  day  and  the  membrane  of 
the  gum  pressed  back,  so  as  to  fully  expose  the  surface  of  the 
fracture.  The  form  of  the  root  is  then  in  a  measure  restored 
with  amalgam,  which,  when  hard,  is  polished  (Figs.  260  and 
261). 

The  root  is  then  crowned,  the  mode  of  operation  being  the 
same  as  in  any  other  case. 


- __       ^ 


V 


132 


ffiZ  <%o+u 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


CROWNING    MOLAR    ROOTS    DECAYED    APART    AT    THE 
BIFURCATION. 


Fig.  262. 


§A 


The  roots  of  a  molar  decayed  apart 
at  the  bifurcation  can  often  be  crowned 
serviceably  by  making  a  cap  for  each 
root  separately,  and  then  soldering  the 
sides  of  the  cap  together  (Fig.  262). 
Where  one  root  is  missing,  the  other 
can  be  crowned  singly. 


DR.   FARRAR'S   CANTILEVER   CROWN. 

Figs.  263  and  264  represent  Dr.  J.  N.  Farrar's  cantilever 
crowns.  He  describes  them  as  follows :  Fig.  263  illustrates  a 
sectional  view  of  three  teeth,  and  an  amputated  first  bicuspid 
root  preserved  by  a  screw,  showing  the  application  of  the  canti- 
lever crown  T  P,  set  upon  the  decayed  second    bicuspid  and 

Fio.  2P.3 


made  to  project  over  to  bridge  the  space  formed  by  the  loss  of 
th^  first  bicuspid,  and  resting  in  contact  with  the  cuspid  so  as  to 
connect  the  broken  line  of  masticating  surfaces  and  prevent 
tilting  forward  of  the  second  bicuspid.  The  abscessed  root  here 
shown  was  extracted.1  Fig.  264  illustrates  the  appearance  of  two 
molars,  the  posterior  half  of  one  of  which  is  destroyed,  showing 
a!-o  tin-  application  of  two  thimble-crowns,  which  are  con- 
structed ho  as  to  form  a  cantilever  bridge  over  the  chasm  by 
locking  midway  in  such  a  manner  as  to  prevenl  tilting  or  sliding 
of  surfaces,  and  at  the  same  time  be  easily  cleansed  by  a  quill 
or  thread. 


1  Denial  Cosmos,  vol.  xxvi,  No.  '•'>. 


CROWNING  IN  CASES  OF  IRREGULARITY. 


133 


METHODS   OF   CROWNING    IN    CASES   OF    IRREGULARITY. 

Fig.  265  shows  a  method  of  treat-  fI(,   265. 

ing  a  case  of  irregularity  without  de- 
stroying the  vitality  of  the  pulp.  The 
tooth  at  B,  which  stood  inside  the  line 
of  the  lower  teeth  when  the  mouth 
was  closed,  was  trimmed,  shaped,  and 
capped.  To  this  cap  was  attached 
the  tooth  at  A,  with  an  oval-shaped 
piece  of  gold  that,  cleared  the  lower 
teeth  in  occlusion.  The  cap  was  then 
cemented  to  the  natural  crown. 

Fig.  266  represents  a  case  of  irregularity  treated  by  Dr.  Bon- 
will,  who  says  in  his  description  of  it, — 

"  This  shows  a  case  of  irregularity  which  was  beyond  correc- 
tion, on  account  of  the  poor  character  of  the  teeth,  their  position 
in  the  palatal  arch,  and  the  age  of  the  patient.     In  such  cases  I 

Fig.  2fi6. 


\)     \i 


do  not  hesitate  to  cut  off  the  crown,  destroy  the  pulp,  and  insert 
an  artificial  crown.  The  crown  is  brought  in  the  circle  and  con- 
nected with  the  root  by  a  strip  of  heavy  gold  plate.  The  plate 
is  attached  to  the  root  with  a  post  or  a  screw  with  a  nut." 


CHAPTER  XIV. 

PARTIAL   CROWNS. 

Gohl. — Partial    crowns  of  gold  for  the  protection  of  plastic 
fillings  in  large  cavities  and  for  the  restoration  of  contour  are 
often  desirable  when,  for  any  reason,  a  solid  metallic  filling  cannot 
well  be  inserted.     The  cavity  having  been  properly  excavated, 
its  orifice  is  trimmed  as  uniformly  straight  or  circular  as  its 
position  and  character  will  allow,  and  the  edge  of  the  enamel 
beveled  off,  tapering  towards  the  center.     In  the  preparation  of 
cavities  in  the  grinding-surface,  trimming  and  cutting  away  the 
enamel    should  be    confined   to  that    surface.      In  approximal 
cavities   which  reach    the    grinding-surtace,   it   is  advisable    to 
extend  them  in  that  surface  and  bring  the  gold  over 
Fio.  267.      and  anchor  it  there,  so  as  to  afford  greater  security 
against  its  displacement  in  mastication.     Where  de- 
cay extends  close  to  the  margin  of  the  gum,  if  the 
tooth  is  trimmed  away  so  that  the  gold  will  extend  just 
under  its  free  edge,  a  recurrence  of  decay  at  that 
point  will  be  avoided.      The  bicuspid   shown  in   Fig.   267  will 
serve  as  a  typical  case  to  illustrate  the  constructive  details. 

The  cavity  having  been  properly  prepared,  a  die  of  the  tooth 
in  its  original  form  is  then  secured.  For  this  purpose  the  mold 
i-  made  by  taking  an  impression  of  the  tooth  with  wax,  making 
;i  plaster  model,  and  then  restoring  the  contour  and  forming 
from  il  the  mold  in  gutta-pereha  or  moldine  ;  or  the  shape  of  the 
natural  tooth  may  be  restored  with  wax  or  gutta-percha  and  the 
mold  made  directly  from  it  in  plaster.  The  die  and  counter- 
die  having  been  formed  (see  article  on  "Molds  and  hies''),  a 
piece  of  pure  gold,  No.  28  to  30  standard  gauge,  the  exact  thick- 
ness being  governed  by  the  size  and  nature  of  the  cavity,  is  struck 
up  to  tie-  form  and  size  of  the  part  to  he  capped.     The  gold  is 

184 


PARTIAL  CROWNS. 


1.-;; 


Fro.  2fi8. 


then  adjusted  to  the  cavity,  to  the  margin  of  which  the  edges 
are  trimmed  and  burnished  to  tit  close  and  flush.  In  the  case 
of  large  cavities  including  a  part  or  the  whole  of  the  approximal 
surface,  a  model  of  the  tooth  and  the  empty  cavity  from  an  im- 
pression taken  in  wax  will  sometimes  facilitate  and  guide  the  pre- 
liminary trimming  and  shaping  of  the  gold.  Two  headed  pins 
fixed  on  the  inside  of  the  cap  (Fig.  268)  are  usually  sufficient 
to  secure  it,  hut  others  can  be  added  if  the  con- 
ditions of  the  case  seem  to  require  it.  In  com- 
pound cavities,  including  one  side  and  the  grind- 
ing-surface,  one  pin  at  least  should  be  fixed  in  the 
latter  portion.  Where  the  grinding  and  both 
approximal  surfaces  are  included,  a  wire  should 
be  extended  from  one  side  to  the  other  (Fig.  269), 
but  the  brace  should  not  touch  the  bottom  of  the 
cavity. 

In  pulpless  teeth  the  pin  from  the  upper  part  of 
the  cap  should  extend  up  the  canal,  giving  great 
stability  in  such  cases  (Fig.  270). 

In  soldering  the  pins  or  loops  when  inserted  in 
holes  drilled  in  the  gold,  a  little  solder  can  be  flowed 
over  the   adjacent  parts  if  deemed  necessary  to 


Fig.  269. 


stiffen  and  strengthen  them. 


Fig.  270. 


Oxyphosphate  is,  as  a  rule,  the  best  to  be  used 
in  connection  with  these  caps,  as  it  forms  a  solid 
and  unyielding  foundation,  and,  when  properly 
protected  from  the  fluids  of  the  mouth  by  a  care- 
fully adjusted  cap,  is  very  durable. 

The  cement  should  be  first  inserted  in  the  cavity, 
and  then  a  small  quantity  placed  around  the  pins 
of  the  cap,  which  should  be  immediately  adjusted  accurately 
in  position.  When  gutta-percha  is  used,  it  is  heated  and  applied 
in  the  same  manner  to  cavity  and  cap.  The  cap  is  then  heated, 
pressed  into  position,  and  held  there  until  the  gutta-percha 
hardens.  This  can  be  hastened  by  the  application  of  cold 
water  from  a  syringe.  The  surplus  of  gutta-percha  is  then 
removed,  and  the  edges  of  the  gold  burnished. 

These  caps  applied  to  teeth  with  living  pulps  show  durability 


O- 


t^L 


5z 

ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

of  a  commendable  character.  The  advantage  they  possess  over 
pieces  of  porcelain  is  found  in  the  close  joint  that  can  be  made 
with  the  edge  of  the  enamel  py  burnishing  the  gold  against  it. 

Dr.  H.  A.  Parr,  in  this  style  of  work,  adapts  No.  60  platinum 
foil  to  the  form  of  the  inner  walls  of  the  cavity  and  just  over  its 
edges  by  the  aid  of  burnishers  and  cotton  twisted  on  the  end  of 
an  instrument,  assisted  by  frequent  annealing  of  the  platinum. 
The  matrix  thus  formed  is  men  filled  with  wax,  chilled,  and 
removed  from  the  cavity  and  invested,  after  which  fine  gold  or 
22-carat  solder  is  melted  into  itTy  The  plug  of  gold  thus  formed 
is  properly  trimmed  and  polished,  and  cemented  in  the  cavity  of 
the  tooth.  When  completed,  it  has  the  appearance  of  a  gold  fill- 
ing. If  necessary,  the  cavity  can  be  previously  partly  filled  with 
amalgam  or  shaped  with  it,  to  give  a  better  form  to  permit  the 
removal  of  the  shell  of  platinum  foil.  Plugs  so  made  can  occa- 
sionally be  utilized  as  an  anchorage  for  bridge-work. 

Dr.  W.  B.  Ames,  of  Chicago,  makes  solid 
gold  tips  for  abraded  pulpless  teeth  in  the  fol- 
lowing manner  for  cases  in  which  he  prefers  not 
to  insert  fillings :  An  opening  is  made  through 
the  occluding  surface  of  the  crown  into  the  root- 
canal.  A  flat  post,  wide  enough  to  fit  closely 
in  the  pulp-chamber  across  its  greatest  diameter, 
thus  tending  to  prevent  anv  rotary  motion  of 
the  gold  tip,  is  then  formed.  A  very  thin 
piece  of  pure  gold  plate,  say  No.  35  American 
gauge,  is  adapted  and  burnished,  with  hand- 
burnishers  and  Ilerbst's  revolving  agate  points, 
into  all  the  irregularities  of  the  abraded  sur- 
face, and  into  the  orifice  of  the  pulp-chamber. 
The  gold  is  then  trimmed  flush  and  even  to  the 
edge.-,  and  burnished  just  over  them.  An  opening  is  next  made 
in  the  gold  cap,  and  through  it  the  post  is  inserted  in  position. 
A  strip  of  thin  gold  plate  or  platinum  foil  is  next  adapted  around 
the  tooth,  well  over  and  above  the  edge  of  the  gold  cap,  and 
trimmed  to  the  length  desired  for  the  tip.  With  the  gold  cap 
and  po.-t  placed  accurately  in  position,  the  cavity  formed  by  the 
strip  of  plate  or  foil  encircling  the  tooth  is  filled  with  wax  cement, 


Fig.  272. 


PARTIAL  CROWNS. 


137 


and  cap,  post,  and  plate  or  foil  removed  and  invested  to  the 
lower  edge  of  the  latter  (see  Fig.  271).  The  investment  is  then 
heated,  and  20-carat  gold  plate  or  20-  or  22-carat  solder  melted 
into  the  matrix  formed  hy  the  plate  or  foil  over  the  cap.  The 
surplus  gold  is  then  trimmed  to  the  edge  of  the  abraded  surface 
of  the  tooth  and  to  the  desired  form  for  the  tip.  When  finished, 
the  gold  tip  is  cemented  in  position  with  a  thin  mixture  of  oxy- 
phosphate.  Fig.  272  gives  a  sectional  view  of  a  central  ineisor 
tipped  in  this  manner.  ^ — 

Porcelain  and  Gold. — The  partial  restoration  with  porcelain  and 
gold  of  an  incisor  crown  such  as  is  shown  in  Fig.  273  is  often  desir- 
able. The  edges  of  the  crown  to  form  the  joining  with  the  porce- 
lain are  trimmed  straight  and  level,  and  then  polished.  A  shallow 
groove  is  generally  formed  to  advantage  at  A,  Fig.  274.  A  very 
thin  piece  of  platinum  is  then  adapted  to  the  crown  as  shown  at  B, 
Fig.  275.  The  pin  C  is  fitted  to  the  root-canal,  passing  through 
the  platinum.  The  post  and  cap  of  platinum  are  then  attached 
with  wax,  removed,  invested,  and  soldered  with  pure  gold.  A 
little  of  the  gold  at  the  same  time  is  flowed  over  the  cap.     The 


Fig  27:?. 


Fig.  274. 


A-' 


Fig. 

T 

'5. 

4 

\ 

V 

i 

) 

cap  and  post  are  then  adjusted  to  the  crown,  and  the  cap  is 
trimmed  level  and  burnished  closely  against  the  surface  of  the 
portion  to  be  restored  and  into  the  groove  at  A,  Fig.  274.  At 
this  stage  of  the  work,  to  facilitate  the  subsequent  operations,  an 
impression  can  be  taken  which  will  remove  in  it  the  cap,  and  from 
this  a  model  can  be  made.  A  cross-pin  porcelain  tooth  is  then 
ground  down  to  a  size  and  shape  that  will  properly  restore 
the  part  and  form  an  accurate  joint  with  the  labial  edge  of 
the  natural  crown.  The  porcelain  is  then  backed,  cemented  to 
the  cap,  removed,  and  soldered  with  20-carat  solder.    The  partial 


138 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


crown  when  properly  finished  is  cemented  in  position  with 
oxyphosphate. 

In  a  ease  such  as  is  represented  in  Fig.  276  the  cap  is  shaped 
to  the  surface  of  the  dentine  and  enamel  at  A  and  over  its  palatal 
edge,  and  the  hacking  on  the  porcelain  is  extended  out  over 
the  palatal  edge  of  the  enamel  at  B.  The  two  sections  of  the 
platinum  are  united  in  the  soldering. 

Fig.  277  illustrates  a  fractured  central  incisor  in  which  the 
pulp  was  not  exposed,  restored  with  porcelain  by  Dr.  J.  Bond 
Littig,  of  New  York.  The  cap  to  the  fractured  part  was 
fastened  by  three  small  pins  as  shown  in  Fig.  278,  which  illus- 
trates the  details  of  the  construction. 


Fig.  276. 


Fig.  277. 


Fig.  278 


Fio,  279. 


••  When-  the  piece  broken  off  is  so  narrow  that  the  porcelain 
tooth  cannot  be  ground  to  fit  in  the  ordinary  way,  without  cut- 
ting out  the  pins,"  Dr.  Littig  describes  hi-  method  as  foil" 
•  First  cut  a  groove  in  the  end  of  the  broken  tooth,  making 
slight  undercuts.    The  pins  of  a  suitable  porcelain  tooth  are  bent 

outward,  and  the  ends  flattened.     The 

porcelain   is   then   ground    away  from 

both  ends,  until  it  is  made  ad  narro 

the   natural  tooth  is  thick  or  near] 

/'"TN      The  piece  is  fitted  to  the  end  of  the  tooth 

I-  \  \     by  placing  the  pins  in  the   groove.     If 

^.j^     \f^T)  J     tn''  .i"'lllt  's  M°t  -""d.  grind  away  from 

either  tooth  or  porcelain  until  it  is  per- 

Then  sel  the  piece  with  zinc-phosphate,  and  after  it  has 

become  hard,  grind  the  tip  to  shape  in  the  mouth,  and  polish 

with  moose-hide  disk  and  pumice-stone.    Fig.  279  illustrates  the 


PARTIAL  CHOWXS. 


139 


md  method;  the  ground  porcelain  tip,  prepared  crown,  and 
restored  tooth  being  shown  separately."  Dr.  Littig's  third 
method  is  to  lirst  cap  the  fractured  part  with  platinum,  allow- 
ing the  ends  of  the  pins,  which  are  soldered  with  pure  gold,  to 
project  below  the  cap.  English  porcelain  body  the  desired 
form  tor  the  tip  is  then  baked  on  the  cap.  The  porcelain  by 
this  method  is  secured  to  the  platinum  forming  the  cap,  by  the 
platinum  pins  embodied  in  it. 

Figs.  280,  281,  and  282  show  how  Dr.  W.  F.  Litch's  pin-and- 
plate  process  may  be  utilized  for  the  attachment  of  porcelain 
tips  for  broken  or  decayed  incisors,  when  the  appearance  of 
gold  fillings  is  obnoxious  to  the  patient.     A  represents  the  por- 

Fig.  280.  Fig.  281.  Fig.  282. 

C  ^ 


mss^ 


Fir,.  283. 


Fin   2^4. 


celain  tips  ;  B,  the  space  to  be  rilled  by  them  ;  C  and  D.  the  open- 
ings for  retaining-pins ;  F  and  G.  openings  in  the  base-plates  (E) 
for  the  pins.  Fig.  282  shows  the  appliance  with  pins  attached. 
Figs.  283  and  284  illustrate  a  case  in  which  the  contour  of  a 
single  incisor  tooth  was  restored  in  this  manner.  Fig.  283  shows 
the  palatal  aspect  of  the  tooth, 
in  which  the  openings  for  two 
retaining-pins  were  drilled,  the 
openings  being  made  quite 
small.  In  Fig.  284  is  seen  the 
porcelain  tip  attached  to  the 
plate  and  read}'  for  mounting. 

The  two  retaining-pins  will  lie  observed  soldered  to  the  plate. 
In  this  case  the  cervical  margin  of  the  natural  tooth  was  made 
level  to  afford  a  secure  resting-place  for  the  porcelain  tip.  The 
appliance  has  been  in  use  for  several  months. 

Dr.  C.  H.  Land,  of  Detroit,  employs  porcelain  partial  crown- 
work  in  cases  of  the  character  here  described.     He  first  forms 


140 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  285. 


a  dovetail  cavity  in  the  central  portion  of  the  section  to  be 
tipped  or  contoured,  and  then  adapts,  aided  by  frequent  an- 
nealing, a  piece  of  platinum  foil  (No.  60  IT.  S.  gauge)  to> 
the  cavity  and  surface  of  the  part,  by  means  of  burnishers, 
and  a  pellet  of  cotton  twisted  on  the  end  of  an  instrument. 
The  platinum  is  then  removed,  and  on  its  surface  porcelain  body 
is  placed,  and  baked  in  the  mutiie  of  a  furnace.      (Dr.  Land's 

Midget  Furnace,  Fig.  285,  is  the 
most  suitable  for  the  purpose, 
as  each  baking  of  the  porcelain 
can  be  performed  in  about  ten 
minutes.)  After  the  first  bak- 
ing, the  thin  platinum,  which  is 
usually  warped  by  the  shrink- 
age of  the  porcelain  body  in  the 
baking,  is  corrected  by  readjust- 
ment to  the  tooth,  in  doing 
which  the  porcelain  is  usually 
fractured.  The  interstices  and 
fractures  in  the  porcelain  are 
then  filled,  the  part  properly 
shaped  with  body,  and  the  por- 
celain rebaked,  and  again  ad- 
justed and  fitted  in  position. 
The  platinum  is  next  trimmed 
free  of  the  edge  with  a  corun- 
dum-wheel, and  the  porcelain 
shaped  accurately  to  the  form 
desired.  Any  imperfections 
existing  are  again  filled  with  body,  and  the  final  baking  given. 

Dr.  Land  claims  that  in  such  cases  porcelain,  if  fitted  to  the 
irregularities  of  the  cavity,  will  be  securely  retained  when 
cemented  with  oxyphosphate.  An  additional  attachment  is 
obtained  by  placing  a  piece  of  iridio-platinum  wire  across  the 
retaining  cavity  of  the  tooth,  with  the  ends  caught  or  bent 
against  the  sides,  and  then  forming  a  dovetailed  groove  across- 
the  base  of  the  porcelain  tip,  which  will  receive  the  wire.  When 
a  porcelain  tip  is  desired  without  the  platinum  base,  alter  the 


PARTIAL  CROWNS.  141 

final  baking,  the  platinum  is  removed  by  tearing  it  off  the  por- 
celain. When  this  is  the  intention,  the  platinum  should  not  pre- 
viously be  trimmed  close,  but  should  be  left  extending  around 

Fig.  28G. 


and  slightly  beyond  the  edge  of  the  porcelain.  Fig.  286  illus- 
trates a  case  of  atrophy,1  in  which  the  tips  of  the  central  incisors 
were  contoured  with  porcelain  by  Dr.  Land.  The  right  central 
shows  the  porcelain  in  position,  and  the  left  the  porcelain  tip 
ready  to  be  adjusted. 

1  This  operation  was  performed  by  Dr.  Land  at  the  meeting  of  the  First  District 
Dental  Society  of  the  State  of  New  York,  in  January,  1889. 


CHAPTER  XV. 


FINISHING  AND  POLISHING— PROCESS  OF  CEMENTATION. 
FINISHING   AND    POLISHING   CROWN-WORK. 

The  finishing  should  be  done  with  small  corundum-wheels 
and  points,  first  coarse,  then  fine,  on  the  dental  engine,  which, 
for  this  part  of  the  work,  is  preferable  to  tiles  or  the  lathe.  In 
the  final  finishing  use  moose-hide  points  with  fine  pumice  on 
the  engine,  or  felt  wheels  on  the  lathe:  and,  in  the  polishing,  a 
brush  wheel,  with  whiting  and  rouge  on  the  lathe. 

The  gold  should  first  be  properly  shaped,  which  includes 
trimming  the  collar  off  to  a  fine  ^d^i^  where  it  fit<  under  the 
gum,  bo  that  the  seam  of  union  with  the  root  will  be  impercep- 
tible. The  gold  that  has  been  placed  on  the  incisive  edge  of  the 
incisor  and  cuspid  crowns  should  be  trimmed  away,  so  that 
although  it  will  protect  the  porcelain,  very  little  if  any  will  be 
when  the  crown  is  in  position  in  the  mouth. 

INSERTION    AND   CEMENTATION. 

Tii  the  insertion  and  cementation  of  all  crown-  and  bridge-work, 
the  object  to  be  effected  is  the  same  in  principle,  that  is,  to  form 
ith  an  insoluble  material  a  solid,  substantial,  and  impervious 
union  b<  twe<  n  the  natural  tooth  or  root  presented  and  the  arti- 
ficial crowmVAs  a  cement  for  this  purpose,  the  plastic  oxyphos- 
phate  of  zinc  is  generally  liF^"'^*  5Jii'LJ,t  lB  '"  "i:lll.v  respects 
one  of  the  mosl  4*i*i  imlifc.  luiWbund. 

ientific  proportions  of  the  chemical  substance  of  whicj 
the  cement  i-  composed  are  essential  in  its  preparation (Mxm  the 

uuld  l>e  in  a  \*-\  v  line  powder.      A  Ktundard  jhv- 

itiuuuT  lllU  I'llllPPiil    h  mill  li      il     i    1     Kor  all  st  vies  ol" crowns 

with  collars,  and  for  bridge-work  depending  <>n  crowns  of  similar 

lu  v,.»gUintf  LLiiiMiit  should  by  »*♦*!,  but  for  cro 


IS)        r^c    , 


/£^y     £7^      £r-ir  <U+~a  e/2 

/; 

h 


GU-+L 


TNSERf ION  AND  CEMENTATION.  _  ]4:} 

without  a   ferrule  or  collar  tin-  nrdimwy  cement  io/ffrofcrabh-. 


For  mixing  the  cement,  a  piece  of  plate-glass  about  five  inches 
long  and  three  inches  wide  as  a  slab,  and  a  small  spatula,  are 
suitable.  The  surface  of  the  slab  must  be  perfectly  clean.  The 
acid  and  powder  should  first  be  separately  ptltced  on  the  gli 
the  amount  of  powder  being  fully  equal  to  the  requirements  of 
the  acid.  fehould  it  be  found  during  th*-mixirrg  that  the  pro- 
portion of  powder  is  too  great.ttho.  surphiisl  should  be  instantly 
thrown  off  the  slab  and  the  mixing,  which  must  be  rapid  and 
thorough,  continued ;  the  consistence  should  be  that  of  thick 
cream,  r  If  the  slah  is  placed  on  a  towel  which  has  been  saturated 
with  ice-water,  the  cold  will  retard  the  setting,  which  is  quite  an 
advantage  in  many  cases.  Iyi'  this  respect  the  side  of  a  square 
bottle  tilled  with  ice-water  a/hd  corked  is  preferable  to  a  slah. 

/  Fro.  287. 


The  parts  to  be  crowned  should  be  previously  syringed  with 
water,  then  protected  by  a  napkin,  bathed  with  alcohol1  applied 
on  cotton  with  tweezers,  and  wiped  witb  bibulous  paper.  Each 
cap  or  crown,  which  should  have  been  thoroughly  dried,  is  first 
tilled  with  enough  cement  to  insure  a  slight  surplus.  A  small 
portion  is  then  put  in  each  root-canal  or  hollow  part  of  a  natural 
crown  present,  and  the  artificial  crown  or  bridge  immediately 
adjusted  in  position.  In  many  cases  it  is  best  to  quickly  remove 
the  napkin  and  occlude  the  teeth' to  insure  the  occlusion,  and 
then  open  the  mouth  and  replace  the  napkin.  The  crown  or 
bridge  should  be  held  under  a  slight  pressure  until  the  cement 
sets.  For  this  purpose  a  piece  of  wood  notched  on  the  end  or 
an  adjuster  (Fig.  287)  can  be  used.        v. 

When  the  cement  has  set  perfectly  hard,  the  surplus  around 
the  edges  should  be  removed.  In  collar  or  shell  crowns  the 
edges  of  the  gold  of  the  collar  or  shell  should  be  given  a  final 


1  Alcohol  used  in  this  manner  not  only  aids  in  drying  the  parts,  but  acts  as  a 
styptic  on  any  lacerated  portion  of  the  gingival  margin. 

i 


p\>i**r* 


' 


■  1 


r^ 


144  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

burnishing.  "Wet  floss  silk  or  dental  fiber,  charged  with  pumice, 
should  be  passed  between  and  around  the  teeth  to  remove  every 
particle  of  the  superfluous  cement,  and  finally  the  parts  should 
be  syringed  with  tepid  water. 

The  patient  should  be  requested  to  call  in  a  few  days,  so  that 
an  examination  maybe  made  to  see  if  any  particles  of  the  cement 
were  overlooked.  Cleansing  gently  at  this  time  facilitates  the 
healing  of  the  gum  around  the  collar  or  neck.  Care  in  these 
little  details  tends  to  prevent  that  inflamed  appearance  and  reces- 
sion of  the  gum  often  seen  around  crowns,  and  also  insures  a 
satisfactory  result  to  the  patient  and  commendation  to  the  dentist. 

Previous  to  insertion  the  posts  of  crowns  should  be  slightly 
barbed.  In  all-gold  cap  crowns  a  vent  for  the  escape  of  air  and 
surplus  cement  is  usually  made  in  the  form  of  a  small  hole  in 
the*  deepest  fissure  of  the  grinding-surface.  \  When  the  cement 
is  jhard,  the  hole  must  in  all  cases  be  closed  with  a  gold  or  amal- 

fm  filling. 
When  gutta-percha  is  used  for  cementing,  the  cavity  in  the 
root  and  crown  having  been  moistened  with  chloroform  and  then 
■dried  and  heated  by  a  hot-air  syringe,  a  portion  of  the  gutta- 
percha is  inserted  and  caused  to  adhere  to  the  sides.  The  post 
and  the  crown  are  then  heated,  the  proper  quantity  of  the  gutta- 
percha attached,  and  the  crown  inserted.  When  the  gutta-percha 
is  cold,  the  surplus  is  removed  with  a  sharp  instrument,  and  the 
edges  smoothed  by  drawing  back  and  forth  against  them  some 
twisted  fibers  of  cotton  saturated  with  chloroform.  Sometimes 
the  post  can  be  fastened  with  oxyphosphate  and  the  end  of  the 
root  and  artificial  crown  joined  with  gutta-percha.  In  such  a 
«ase  the  crown  should  be  heated  and  the  gutta-percha,  rolled 
down  very  thin,  placed  on  the  edges  to  be  united  in  the  form  of 
a  perforated  disk.  The  crown  is  then  pressed  to  position  in  the 
oxyphosphate  placed  in  the  root.  The  order  of  the  use  of  these 
materials  can  be  reversed  where  it  may  be  desirable  at  some 
future  time  to  easily  remove  the  crown.  Bridge-work  can  be 
conveniently  attached  temporarily  with  gutta-percha.  In  this 
event  a  quantity  barely  sufficient  to  fasten  the  caps  should  be 
used.  Gutta-percha  does  no1  possess  sufficient  rigidity  .for 
general  use  in  hridge-work. 


:.o /h*—     &ern*u.  eZiot.   $rj$j[  ^£_ 


'  <r 


h~-tfu<T~t*+  &i Jet      PrfUsT-    J^tt^fCj 


BRIDGE- WOKK. 


The  artificial  replacement  of  the  loss  of  a  portion  of  the  teeth 
by  bridging  the  vacant  spaces  with  substitutes,  supported  in  posi- 
tion by  means  of  their  attachment  to  adjoining  or  intervening 
natural  teeth,  is,  as  we  have  seen  in  the  introduction,  of  antique 
origin,  having  been  practiced  long  before  plates  came  into  use. 
Fig.  288.  Fig.  289. 


Originally,  the   application    and   mechanical    construction  of 

such  dentures  was  of  a  most  primitive  character;   and  as  the 

attachments  were  simply  ligatures  or  clasps  of  gold,  the  teeth 

wore     more    ornamental    than 

Fig.  290. 

useful.    Figs.  288,  289,  and  290 

illustrate  the  antique  methods.1 

Fig.  288  is  an  illustration  of  a 

specimen  of  ancient  Phoenician    ffi 

dentistry.     Fig.  289  is  that  of 

one  in  the  Etruscan  age,  dating  about  five  hundred  years  B.C. 

Fiir.  290  o-ives  a  view  of  the  same  denture  inverted. 

Dentures  constructed  on  the  bridging  plan  by  various  methods 
have  been  occasionally  employed  from  the  earliest  days  of  modern 

JSee  Independent  Practitioner,  vols,  vi  and  vii,  "  Evidences  of  Prehistoric  Den- 
tistry," by  J.  G.  Van  Marter,  D.D.S.,  Rome,  Italy.  Figs.  288,  289,  290  are  copies 
of  the  illustrations  of  the  specimens,  the  first  of  which  is  represented  as  being 
in  the   museum  of  the  Louvre,  Paris,  France,  and  the  second  in  the  Corneto 

Museum,  Corneto,  Italy. 

'  147 


*         /yLCbSx^n-    lno^>i.<Jk^       /&3/J. 


143 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


dentistry,  though  until  4iiito  recently  the  system  has  not  obtained 
general  recognition  nor  been  extensively  practiced. 

Den/al  literature  presents  bridging  operations  as  described  by 
J.  B.YGariot  in  1805,  C.  F.  Delabarre  in  1820,  Dr.  S.  S.  Fitch  in 
1829J  and  Dr.  W.  II.  Dwindle  in  1856.  Figs.  291  and  292 
are  copies  of  illustrations  in  Dr.  Fitch's  work,  published  in 
New  York  in  1829,  and  Fig.  293  one  from  a  translation  of  F. 
Maury's  work  in  1843.  In  1871  the  bridging  process  or  bridge 
principle  was  again  brought  to  notice  by  a  patent  applied  for  in 
England  by  Dr.  B.  J.  Bing,  of  Paris,  for  an  improved  means  of 
supporting  and  securing  a  bridge  by  anchoring  with  cement  or 


Fig  291. 


Fig.  292. 


Fig.  294. 
c    c     cz  a-    a,  o  c 


fillings  clasps  or  bars  extending  from  it  into  holes  formed  in  the 
adjoining  teeth  (Fig.  294).  The  system  was  also  practiced  in 
operations  by  the  late  Dr.  M.  II.  Webb,  and  is  described  in  his 
"  Notes  on  Operative  Dentistry." 

The  facilities  afforded  by  the  artificial  crown-work  now  in 
vogue  for  supporting  and  securing  bridge-dentures  have  caused 
a  revival  of  the  system  in  an  improved  form,  termed  "  Bridge- 
Work,"  in  which  artificial  crowns  cemented  to  natural  teeth  or 
root-  are  employed  ;i^  abutments  to  support  artificial  teeth  which 


BRIDGE-WORK.  149 

span  or  bridge  the  spaces  between  them.  These  bridges  are  so- 
devised,  in  the  best  methods,  that  while  supplying  the  patient 
with  the  means  of  masticating  his  food  the  cleanliness  of  the 
denture  is  also  provided  for. 

Ordinarily,  bridge-work  is  immovably  cemented  in  position^ 
The  claims  set  up  in  its  favor  are  as  follows : 

First.  The  perfect  replacement  of  lost  teeth  by  artificial  onesy 
and  without  the  use  of  a  plate. 

Second.  The  absence  of  any  mechanical  contrivance  to  inter- 
fere with  the  tongue  in  articulation. 

Third.  The  natural  teeth  are  not  abraded  by  the  presence  of 
clasps,  the  functions  of  the  sense  of  taste  are  more  perfectly 
performed,  and  a  healthy  condition  of  the  tissues  preserved, 
because  the  gums  and  palate  are  not  covered  over  with  a  plate. 

Fourth.  The  solidity  and  immovability  of  the  denture  at  all 
times,  both  in  speech  and  mastication. 

Fifth.  The  weight  of  the  denture  and  the  strain  of  mastica- 
tion fait/on  the  natural  teeth,  which  are  better  suited  to  sustain 
them  than  the  contiguous  alveolar  surfaces. 

Sixth.  Its  special  adaptation  to  the  replacement  of  single 
teeth,  or  of  a  small  number,  where  bridge-work  is  usually 
superior  to  any  other  device. 

Seventh.  While  all  operations  performed  for  the  restoration 
of  lost  teeth,  like  other  remedial  operations,  are  temporary  rather 
than  permanent  in  their  results,  bridge-work  as  regards  per- 
manency takes  equal  rank  with  any  other  operative  procedure. 

The  following,  on  the  other  hand,  are  the  objections  raised 
against  bridge-work : 

First.  It  fails  to  restore  the  contour  of  the  soft  tissues  above 
the  bridge,  as  artificial  gums  cannot  properly  be  used  in  this 
style  of  work. 

Second.  The  slots  beveled  under  the  artificial  teeth,  called 
self-cleansing  spaces,  fill  with  particles  of  food. 


150  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

Third.  The  speech  of  the  wearer  is  often  affected  by  these 
self-cleansing  slots  under  the  front  teeth. 

Fourth.  The  teeth  employed  as  abutments  are  usually  irre- 
parably destroyed  by  the  process  of  crowning. 

Fifth.  If  an  extensive  bridge  is  made  of  gold,  being  im- 
movable, it  is  impossible  to  keep  it  perfectly  clean,  as  the  metal 
will  gradually  tarnish  in  parts  out  of  reach  of  the  brush,  and 
will  gather  offensive  matter  on  its  surface  and  in  its  interstices. 

Sixth.  In  cases  where  it  becomes  necessary  to  temporarily 
remove  the  bridge  for  the  purpose  of  repair,  or  because  of  dis- 
ease in  the  teeth  which  support  it,  the  operation  is  difficult  and 
the  bridge  is  usually  injured  so  as  to  unfit  it  for  reinsertion. 

Seventh.  The  teeth  which  support  the  bridge  are  required  to 
bear  more  force  and  pressure  than  nature  intended, — where  the 
piece  is  large  many  times  more, — and,  the  bridge  being  perma- 
nently attached,  at  no  time  can  any  rest  be  given  the  abutments 
or  the  contiguous  parts  by  its  temporary  removal.  Thus  in  a 
piece  of  bridge-work  consisting  of  fourteen  teeth  supported  by 
four  natural  ones,  each  one  of  the  natural  teeth  may  have  to 
bear  more  than  three  times  the  strain  in  supporting  the  weight 
of  the  denture  and  the  force  of  mastication,  that  was  intended. 
The  ultimate  result  is  evident  to  any  one  who  is  experienced 
in  dental  practice;  and  unless  the  anatomical  conditions  are 
most  favorable,  the  usefulness  and  durability  of  such  work  is 
decidedly  limited  in  character,  considering  the  time,  trouble, 
and  greal  expense  attending  it. 

Such  are  the  objections  which  have  been  put  forth  against 
bridge-work;  and  yet,  whatever  may  be  urged  against  it,  its 
advantages  have  won  from  a  majority  of  the  profession,  includ- 
ing many  accepted  authorities,  an  enthusiastic,  almost  a  sen- 
sational, indorsement;  some  practitioners  even  going  so  far  as 
to  proclaim  it  the  only  true  method  for  the  insertion  of  artificial 
teeth. 


BRIDGE-  WORK.  151 

Judged  impartially,  bridge-work  has  many  advantages  when 
practiced  by  experts  who  properly  construct  and  apply  it. 
Without  doubt  it  has  been  abused.  Bridges  have  been  inserted 
where  the  support  was  insufficient,  or  the  construction  was  wrong 
in  principle  or  faulty  from  lack  of  skill.  More  than  this  :  bridge- 
work  has  been  passing  through  the  experimental  period,  when 
failures  are  apt  to  appear  more  prominently  than  successes. 
The  chronicles  of  dental  literature,  however,  in  this  respect  offer 
only  a  repetition  of  the  historical  difficulties  that  attend  all  new 
departures  in  the  arts. 


CHAPTER    I. 

CONSTRUCTION    OF   BRIDGE-WORK. 

To  the  skilled  mechanical  dentist,  well  versed  in  metal-  and 
crown-work,  bridge-work  does  not  present  extreme  difficulty. 
The  foundations  or  abutments — that  is,  the  teeth  or  roots  on 
which  the  bridge  will  rest — are  first  to  be  considered,  due  respect 
being  paid  to  the  mechanical  principles  controlling  the  leverage 
and  the  force  of  occlusion  in  mastication.  The  amount  of  strain 
that  can  be  borne  by  the  different  teeth,  individually  and  collect- 
ively, according  to  their  position  and  condition  of  health,  should 
be  carefully  calculated.  As  a  rule,  the  force  exerted  upon  the 
incisors  in  occlusion  will  be  directed  outward  on  the  upper,  and 
inward  on  the  lower  teeth,  and  its  tendency  when  they  support 
a  bridge  will  be  to  gradually  push  them  out  of  line  in  each  direc- 
tion. When  the  incisors  are  replaced  by  a  bridge,  the  tendency 
of  the  force  of  occlusion  is  toward  a  similar  result.  On  the 
bicuspids  and  molars  the  force  is  direct.  The  rules  which  govern 
the  number  and  position  of  the  teeth  or  roots  that  are  required 
as  foundations  for  bridges  in  practice,  are  as  follows : 

One  central  root  will  support  two  centrals,  and  if  spurs  or 
bars  from  the  sides  of  the  bridge  rest  upon  or  are  anchored  in 
the  adjoining  teeth,  a  lateral  in  addition. 

Two  central  roots  will  support  the  four  incisors,  spurs  or  bars 
resting  on  or  anchored  in  the  cuspids  to  be  used  additionally,  if 
the  case  requires  them. 

The  cuspid  roots,  alone  or  with  the  aid  of  a  central  root,  will 
support  the  six  anterior  teeth. 

One  molar  or  bicuspid  on  one  side,  and  a  bicuspid  or  molar 
on  the  other,  with  one  or  two  roots  in  an  intermediate  position, 
will  support  a  bridge  between  them. 

One  righl  and  one  left  molar,  with  tin-  assistance  of  the  two 
cuspids,  will  support  a  bridge  comprising  fin'  entire  arch. 

A  bridge  on  one  side  of  the  mouth  can  l»e  supported  by  two 
162 


CONSTRUCTION  OF  BRIDGE-WORK. 


153 


or  three  teeth  or  roots  on  that  side.     The  cuspids  always  afford 
the  most  reliable  support. 

In  general,  the  application  of  these  principles  will  cover  the 
subject  of  foundations,  the  operator  being  governed  by  the  exact 
condition  of  individual  cases.  In  a  bridge  of  the  six  anterior, 
teeth  on  the  two  cuspids,  when  the  articulation  of  the  antagon- 
izing teeth  is  close  and  deep,  the  strain  should  be  relieved  by  an 
additional  attachment  of  the  bridge  to  the  teeth  posterior  to  the 

cuspids. 

Fia.  295. 


The  preparation  of  teeth  or  roots  to  support  a  bridge  is  the 
same  as  for  ordinary  crowns,  except  that  the  trimming  of  the  sides 
and  the  drilling  of  the  root-canals  of  the  various  anchorages 
should  be,  as  far  as  possible,  in  parallel  lines,  so  that  the  collars 
and  posts  of  the  crowns  shall  move  readily  to  their  places  in  the 
adjustment  of  the  finished  bridge.  Teeth  or  roots  which  are  to 
be  crowned  with  all-gold  cap  crowns  are  crowned  by  some  one 
of  the  methods  described.  Those  on  which  porcelain  fronts  are 
to  be  used  are  merely  capped,  the  posts  being  soldered  and 
allowed  to  project  a  short  distance  beyond  the  caps. 

The  case  represented  in  Fig.  295  will  be  used  to  illustrate  the 
construction  of  a  piece  of  bridge-work  in  all  its  details.  The 
abutments,  or  supports,  consist  of  the  right  second  molar  capped 
with  an  all-gold  crown,  constructed  in  sections  by  first  forming 


154 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


the  collar  and  then  soldering  on  the  cap  (see  page  95),  the  two 
cuspid  roots  capped  for  collar  crowns  with  porcelain  fronts  (see 
page  89),  and  the  left  first  molar,  which  will  afford  anchorage 
to  a  bar  on  that  side  of  the  bridge  (Fig.  296).  A  slot,  dovetail 
in  form,  is  usually  cut  well  into  the  body,  but  not  to  an  extent 
that  will  endanger  the  pulp  of  the  last-named  crown  (Fig.  297). 
If  the  tooth  is  not  decayed,  it  can  be  first  opened  up  with  a 
rubber  and  corundum  disk.  The  shaping  of  the  slot  is  best 
accomplished  with  fissure-burs.  With  the  crowns  and  caps  in 
position,  an  impression  and  articulation  of  the  case  are  then 


Fig.  296. 


Fig.  207. 


taken  with  plaster  slightly  colored  with  carmine.  The  plaster 
is  mixed  moderately  thick  and,  with  the  aid  of  a  spoon,  placed 
around  in  the  mouth  on  the  crowns,  caps,  and  parts  to  be 
included  in  the  bridge,  and  the  antagonizing  teeth  occluded 
tightly  and  so  held  until  the  plaster  sets.  The  mouth  is  then 
opened  and  the  plaster  carefully  removed,  the  pieces  being 
adjusted  together  should  it  break.  The  crowns  and  caps  (the 
latter  held  more  firmly  by  the  protruding  ends  of  the  pins)  are 
removed  in  it.  The  plaster  is  then  varnished,  and,  on  the  side 
containing  the  crown-,  a  model  is  run,  composed  of  equal  parts 
of'  calcined  marble-dust  and  plaster,  to  which  is  added  a  little 
sulphate  of  potassium, — less  than  the  proportion  of  salt  generally 
used, — which  causes  the  mixture  to  set  hard  quickly.     When  the 


CONSTRUCTION  OF  BRIDGE-WORK. 


155 


model  has  set,  it  is  mounted  with  plaster  on  an  articulator,  and 
the  other  side  of  the  colored  plaster  impression  giving  the 
articulation  is  run  with  plaster  and  the  opposite  section  of  the 
articulator  adjusted,  all  at  the  same  time.     When  the  impres- 


Fio   298. 


sion  plaster  is  removed  (an  operation  which  is  greatly  facilitated 
by  its  having  been  colored  with  carmine),  a  correct  model  and 
articulation    of  the  case  will  he  found,  with  the    crowns   and 

/  /  ^£PS  m  exact  position  as  in  the  mouth  (Fig.  298). 

■y      ^Another  method  is  to  first  take 

/  the  impression  in  an  impression- 
tray,  and  then  the  articulation  in 
wax.  and  make  a  model  and  ar- 
ticulation from  them  in  the  usual 


Fig.  299. 


manner.- 

The  pins  protruding  from  the 
cape  on  the  model  are  next  cut  ofl* 
short.  Teeth  are  selected, — ordi- 
naryf  plate  teeth  for  the  incisors  and 
cuspids,  and  partial  teeth,  repre- 
senting the  front  section  of  the 
tooth  and  styled  porcelain  facings, 

which  were  specially  designed  for  crown-  ai*#  bridge-work,  for 
the  bicuspids  and  molars  (Fig.  299).  Cuspids  are  sometimes 
used  to  form  the  fronts  for  bicuspids.  The  teeth  are  ground 
.and   fitted  to  the    model    and    articulation,  so   that   the   labial 


-.-, 


^ 


-L 


156 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


upper  edge  of  the  teeth  shall  press  lightly  on  the  gum.  Those 
which  are  intended  to  form  the  fronts  of  the  caps  on  the  cuspid 
roots  should  be  adjusted  in  the  ordinary  manner  for  single 
crowns.  To  determine,  the  proper  positions  of  the  teeth  for 
producing  the  best  appearance,  they  can  be  adjusted  in  the  mouth 
on  wax,  without  the  gold  crowns  or  caps  of  the  supports. 
The  correct  position  of  the  teeth  on  the  model  having  been 
obtained,  investing  material,  composed  of  one  part  plaster  to 
two  of  calcined  marble-dust,  is  placed  on  the  outside  of  the 
model  on  the  labial  aspect  oil  the  teeth,  merely  sufficient  in 


A   and   B,   central   incisor  and    bicuspid   ready   for  metallic  bucking.      C,  i«  a  central    backed. 
D,  D,  D,  porcelain  fronts  as   they  appear  on   insertion  after  the  process  of  backing,   capping, 
soldering. 

quantity  to  hold  them  in  position,  thus  forming  a  matrix. 
The  wax  is  then  removed,  exposing  the  palatal  portion,  and 
permitting  their  form,  and  position  to  be  studied  (Fig.  300). 
Tin-  porcelain  teeth  amti  fronts,  with  the  exception  of  fronts 
for    the    roots    capped,    are    then     removed    from    their    invest? 

ment,  and  the  base  ground  from  a  line  on  the  palatal  side 
below  the  pins, straight  to  the  labio-cervical  edge  (A  and  B,  Fig. 
800).      This  is  to  form    the   Belf-cleansing  spaces,  if-  ti— y  nrn 


'  ONSTRUCTION  OF  BRIDGE-WORK. 


157 


J.jiruil.  The  incisors  are  then  backed,  using  either  very  thin 
platinum  or  pure  gold  (C).  The  barkings  are  allowed  to  extend 
just  over  the  incisive  edge  as  a  protection  to  it,  and,  if  preferred, 
down  on  the  curve  of  the  self-cleansing  space.  A  more  desirable 
result  is  secured  if  the  backing  extends  only  to  the  edge  of  the 
self-cleansing  space,  and  the  porcelain  is  polished,  as  its  surface 

is  superior  in  cleanliness  to  that  of-gold.  5^*r 

The    bicuspid    and    molar    porcelain^fr^mts,  their  tips  being 
1  ground  off  (A  Fig.  301),  are  lined  in  thji  name  manner.     A  cap 


i 


of  pure   goldybr  gold  lined  with    platinum,  representing  the 
grinding-surface  of  each  tooth,  is  struck  up  as  described  and 


Fig.  301. 


Fig.  302. 


v 


illustrated  in  the  construction  of  gold  crowns  (see  page  99),  and 
the  concave  portion  filled  by  melting  in  scraps  of  20-carat  gold 
plate.  The  surface  is  then  ground  smooth  (B),  and  closely  fitted 
to  the  tip  of  the  porcelain  front  to  form  the  occluding  surface 
in  accordance  with  the  articulation  of  the  lower  teeth,  and  the 
space  filled  in  with  wax.  This  metallic  occluding  surface  is  to 
protect  the  porcelain.  Triangular  pieces  of  very  thin  gold  plate 
-or  platinum  foityfC)  are  then  cut  and  fitted  to  the  side-. 
which  they  should  extend  slightly/^fcjphe  tooth  is  invested 
leaving  the  back  open,  presenting  the  form  of  a  pocket  (Fig.  302) 

The  bar  intended  to  be  anchored  in  the  slot  cut 
in  the  molar  on  the  left  side  is  made  of  iridio-plat- 
inum  wire,  about  No.  15  U.  8.  standard  gauge,  with 
the  end  shaped  as  shown  in  Fig.  303,  and  fastened 
with  wax  to  the  tooth  and  cap,  and  adjusted  in  the 
mcmth  to  obtain  accuracy  of  position  before  soldering. 

All  the  .teeth  should  beln  vested  at  the  same  time, 
sore  and  porcelain  fronts  to  the  cuspid  crowns  as  shown  in  Fig. 
3-04.     In  the  soldering,  20-carat  gold  plate  si»o>al&be  melted  into 


flvuvd 


Fig.  303. 


' 


, 


z—¥— — • — - 

Y.tS  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK, 


the  pockets  formed  by  the  cap  and  side  pieces  to  fill  out  to  the 
line '  at  A,  Fig.  306,  and  flowed  over  the  backings  of  the 
incisors  and  cuspid  fronts  in  sufficient  quantity  to  shape  them  as 
shown  at  B,  Fig.  306.  V  The  teeth  forming  the  bridge  between 
the  crowns  are  called  "  dummies."      After  the  solderino-  and 


Fig.  304. 


Fig.  305. 


Vfc+*  (Y»JX* 


removal  of  the  borax  with  acid,\6ach  tooth  is  then,  when  it  is   J 
easily  done,  very  carefully  trimmed  and  finished.  *< 

The  teeth  are  next  placed  in  their  relative  positions  on  the 
model  as  shown  at  D,  D,  D,  Fig.  300,  and  attached  with  wax. 
The  model  is  then  detached  from  the  articulator,  trimmed  down 

Fig.  306.  \^J 

J 


Fig.  307. 


f-  yl*- 


a-  much  as  possible  in  size,  and  additional  investing  material, 
composed  of  two  parts  marble-dust  and  one  of  plasterV^pplied 
until  all  of  the  bridge  is  covered  except  the  space  along  the 
backings  and  crowns  where  they  are  to  be  united  in  the  solder-: 
ing.     To  prevent  fracture  during  the  process  of  soldering,  which 


yv  au,V' 


COXSTh'U'TloX  OF  BRIDGE-WORK. 


159 


Fig.  308. 


might  readily  occur  from  contraction  in  so  large  an  investment, 
an  iron  wire  or  a  narrow  horse-shoe  shaped  strip  of  sheet  iron 
should  be  placed  in  the  investment  so  as  to  encircle  the  teeth 
and  crowns  about  one-fourth  of  an  inch  from  their  exterior  sur- 
face (Fig.  307).  In  "fibe  spaces  between  the  backings  pieces  of 
gold  or  platinum  plate  or  wire,  about  one-eighth  of  aii  inch 
long,  are  placed  lengthwise,  and  the  joints  well  soldered  V(wi 
20-carat  gold  sokler.  The  soldering  is  best  done  with  a  gas  blow- 
pipe on  a  piece  of  charcoal  with  a  concave  depression.  When  the 
bridge  is  removed  for  finishing,  the  joints  of  the  backings  and 
crowns  are  finished  with  corundum-wheels  and  points  and  moose- 
hide  points  on  the  engine,  and  the  entire  bridge  finely  polished 
with  whiting  carried  by  a  brush-wheel  on  the  lathe.  Any  little 
pita  that  may  exist  can  be  filled  in  with  gold  foil.  The  bridge 
is  then  ready  for  insertion  (Fig. 
308).  If  the  constructive  details 
have  been  properly  performed 
as  described,  a  finished  piece 
of  bridge-work  is  the  result. 

In  constructing  bridge-work 
many  prefer,  after  the  porcelain 
fronts  are  backed  and  the  caps 
forming  the  occluding  surfaces 
of  the  bicuspids  and  molars  are 
properly  adjusted  on  the  model, 
to  invest  and  do  the  entire  sol- 
dering at  once.  When  this  plan 
is  followed,  pieces  of  gold  wire  should  be  laid  lengthwise  in  the 
slots  under  the  gold  caps  of  the  porcelain  fronts,  and  the  parts 
filled  in  and  all  the  sections^  f  the  bridge  joined  together  in 
the  soldering.  By  this  nietKod  there  is  less  liability  of  fracturing 
the  porcelain  fronts,  butythe  finishing  of  the  bridge  is  not  so 
easily  or  so  perfectly  done. 

In  large  pieces  of  work  thai-A  ia  anm^  ljnhi1if-y.tr>  warping, 
which  may  be  avoided,  whichever  method  of  soldering  is 
adopted,  by  first  removing,  in  proper  position,  the  "  dummies  " 
and 'soldering  those  of  each  span  together.  The  spans  are  then 
replaced  in  the  matrix  and  soldered  to  the  abutments. 


160 


ARTIFICIAL  (h'OWX-  AND  BRIDGE-WORK. 


N 


Adjustment  ami  Attachment — The  bridge  when  finished  is  ad- 
justed in  the  mouth,  every  point  carefully  examined,  and  any 
alterations  required  are  then  made.  Should  the  edges  of  the 
collars  of  any  of  the  crowns  catch,  so  as  to  prevent  their  being 

Fio.  300. 


placed  in  position,  a  small  quantity  of  articulating  paste  should 
be  applied  and  the  point  found  and  trimmed  off.  If  extensive 
warping  has  occurred  in  the  soldering,  the  bridge  must  be  sawed 
apart  in  one  or  two  places,  adjusted  in  the  mouth,  and  removed  in 
an  impression-tray,  using  only  sufficient  investing  material  (equal 
part-  of  plaster  and  marble-dust  with  the  usual  quantity  of  sul- 
phate of  potassium)  to  cover  the  points  of  the  teeth  and  crowns 
(Fig.  309).     The  inner  surface  of  the  tray  should  be  oiled. 

FlQ  310  The  bridge  and  the  in- 

vesting material  are  then 
removed  together  from  the 
impression-tray,  and  more 
investing  material  is  added 
to  complete  the  investment. 
Tin:  cul  parts  of  the  bridge 
arc  then  soldered  together. 
When  the  adjustment  of 
the  bridge  is  accomplished, 

fr&aE  :,MiM  '"•  tempora- 
rily/ait itta  p' ■  p •  h ; i"i$t«*«siE£iir.  For  its  permanent 
attachmenl  the  pine  or  posts  of  the  crowns  are  barbed,  and  the 

h  and  root-  to  which  crowns  have  bc-n  tilted  are  then  treated 


COXSTR  U< '  TJON  OF  BR  ID  G  E-  WO  II K. 


161 


the  same  as  single  crowns,  and  the  bridge  cemented  on  with  sf 
rliMW  iTpwiifctf  oxyphosphate  cement  (sec  page  141).     The  end  of 
the  bar  is  anchored  in  the  slot  by  either  a  gold  or  an  amalgam 
rilling.     Fig.  310  represents  the  bridge  in  position. 

The  Construction  of  Small  Pu  a  s  ofBridgi  -work  is  much  simplified 
by  the  following  method  :  Crowns  are  first  made  for  the  teeth  or 
roots  that  form  the  abutments  and  temporarily  placed  in  position. 

Fig.  311. 


Fig.  312 


Fig   313. 


The  teeth — "dummies'* — which  form  the  span  having  been 
ground  and  backed,  are  adjusted  and  cemented  with  resin  and 
wax  in  proper  position  between  the  crowns.  The  crowns  and 
dummies  are  then  removed  together,  in  an  impression-tray  filled 
with  investing  material.  The  inside  of  the  tray  should  be  previ- 
ously/coated with  a  film  of  wax  with  a  serrated  surface.  The  im- 
pression-tray is  then  heated,  and  the  investment  with  the  crowns 

11 


162 


ARTIFhIAL  CROW'S-  ASD  BRIDGE-WORK. 


and  illumines  removed;  more  investing  material  is  then  mixed, 
and  the  exposed  [»arts  of  the  crowns  and  teeth  covered.  The  in- 
vestment, when  set,  is  then  cut  away  sufficiently  to  expose  the 


Fig.  314. 


Fig.  315 


parte  thai  ar  •  to  be  Idled  in  and  united  together  in  the  process 
of  Boldering.  Figs.  311,  312,  313,  33  I,  815  represent  case-  of 
bridge-work  constructed  in  this  maimer. 


(}>    rvt'f 


* 


C  II  APT  Eli    II. 


Fig   316. 


Fig.  317 


SPECIAL    PROCESSES    AND    APPLI  ANCES  IN    BRIDGE-WORK. 

Shoulders  on  the  Amerior^Tetili  are  sometime?  desirable,  especi- 
ally on  the  superior  cuspids  at  the  point  of  occlusion  with  the 
lower  teeth.  A  shoulder  can  be  made  by  melting  gold  plate 
into  the  form  of  a  small  ball  or  globule,  then  flattening  it  out 
and  soldering  it  against  the  backing. 

Another  method  is  to  attach  with 
wax  transversely  across  the  backing 
in  proper  position  a  atrip  of  gold 
plate  as  shown  in  Fig.  316,  and  then 
flow  in  gold  to  the  line  A,  by  spe- 
cially investing  or  in  the  soldering  of 
the  bridge.  Nsv». 

Solid  Gold  Croiims. — In  a  close  articulation,  when  the  patient 
prefers  strength  to  appearance,  the  bicuspids  and  molars  ahouM  Hr^^^ 
he  made  of  solid  gold.  They  are  constructed  by  stamping  up 
the  cap  (A,  Fig.  317)  representing  the  grin  ding-surface  (see 
page  97),  and  then  adjusting  and  cementing  with  wax  a  piece 
<of  plate  cut  and  shaped  to  form  the  front  and  sides  (B),  which  ^  ,  U^ 
is  then  invested  and  filled  in  with  gold  solder,  or,  if  pMBF'gold  lias 
been  used  in  the  sections  of  the  crown,  with  18-  or  20-carat  plate. 

Seamless  .contour  crowns  can  be  used  for  the  purpose  as 
follows:  The  proper  crowns  having  been  selected,  the  gold  is 
trimmed  and  the  crowns  adjusted  in  position  on  the  model.  A 
matrix  of  plaster  is  then  placed  on  the  labial  side,  which  permits 
the  palatal  portion  to  be  studied,  the  crown  removed,  and  out 
awav  to  the  form  required..  They  are  then  removed,  invested, 
an<l  filled  in  witnTgoTiritlaT-.  '  r>_ 

A  bar-bridge  can  be  made  with  theselby  passing  an  iridio- 
platinum  wire  through  the  erowno  before  tilling  in  (Fig.  318). 

163 


liU 


ARTIFICIAL   CROWN-  AND  BRIDGE- WORK. 


.  I  Solid  Grold  Crown  for  a  Pulpless  Molar,  supporting  the  end 
of  a  bar  as  Bhown  in  Fig.  819,  is  constructed  as  follows:  The 
natural  crown  is  ground  down,  banded,  capped,  and  pivoted  as 
in  Fig.  3-20.  The  gold  forming  the  top  of  the  cap  is  made  per- 
fectly tlat  and  left  projecting  a  little  at  the  sides.     A  contoured 


Fio.  318. 


Fig.  319. 


Fio  320. 


crown  of  pure  gold,  or  gold  lined  with  platinum 
aa  a  precaution  against  melting,  is  shortened  suf- 
ficiently to  represent  the  absent  coronal  section 
of  the  tooth,  and  with  a  corundum-disk  the  orifice  V  W 
of  the  anchorage  cavity  is  formed.  A  shell  of  thin  platinum  of 
the  size  and  shape  of  the  anchorage  cavity  is  then  inserted  and 
cemented  with  wax  on  the  inside  of  the  crown.  The  crown  is 
then  invested  and  filled  with  18-carat  gold  solder,  which  should 
be  <ut  into  small  pieces,  and  be  placed  successively  in  the  crown 

Fio.  321. 


and  melted  by  maintaining  a  uniform  heat  with  the  large  Ha  me 
of  a  blow-pipe.  The  base  of  the  crown  is  next  ground  level  and 
accurately  fitted  to  the  cap  and  articulated  to  the  antagonizing 
teeth.  It  is  then  clamped  in  position  to  the  cap,  the  pivots  of 
which  are  protected  with  investing  material  (Fig.  321),  and 
soldered,  making  a  perfect  joint.  This  is  an  easy  method  of 
constructing  an  otherwise  difficull  form  of  crown. 


SI'KCIAL  PROCESSES  AND  APPLIANCES  IX  BRIDGE- WORK.  165 


Fig.  322  illustrates  a  bridge  supported  by  a  bar-anchorage  in 
a  solid  gold  crown  on  the  roots  of  a  molar  and  a  shell  crown  on 
a  cuspid. 

<  'onru  cting  Bands  or  Barsfor  Bridges,  which  obviate  the  removal 
of  crowns  of  intervening  natural  teeth  between  the  sections  of  a 
projected  bridge,  are  formed  by  passing  a  heavy  band  of  oval- 

Fig.  322.  Fig.  323. 


Fig.  324. 


Fro. 


shaped  gold   or   iridio-platinum  wire    around    the    intervening 
teeth,  close  to  but  not  touching  them,  and  resting  lightly  on  the 
gums.     The  application  of  this  device  was  first  illustrated  by 
JDr^J^L.  Williams,  Figs.  323,  324,  and  325. 

Roots?intervemn^)between  the  abutments  of  a  projected  1  nidge 
should  not  iSeTextracted,  but  whenever  practicable  they  should 
be  treated,  filled,  and  trimmed  level  with  the  gum,  as  tliev  can 


166 


ARTIFICIAL   CROWN-  AXD  BUI  DOE- WORK. 


usually  be  made  to  afford  some  support  for  the  bridge,  which  may 
rest  upon  them.  Figs.  326  and  327  represent  acase  in  which  the 
root  of  the  cuspidon  the  right  side  has  been  so  treated  and  utilized. 

Fin.  326. 


i 

Shell  Anchoragi  or  Grown. — Tl**-mjnstrnction  of'?1  s^"'^  ""r-hiu-- 
a.a^-far-M'TUspid    and    it;   practical   application   in   supporting  a 


® 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE- WORK.  167 


*4*cid£** -eamiot  bo  bettor  described  than  in  the  following  word-  oi 
Di\M.  L.  Williams: 

"  Fig.  &28  shows  a  piece  of  workr  made  for  a  cage,  of  quite 
frequent  occurrence.  It  represents  the  restoration  of  tfre  inferior 
bicuspids  and  first  molar  of  the,  right  side"  A^grfld  crown  is 
made  for  the  second  molar,  and  the  throe  intervening  teeth  or 
'  dummies*  are  then  constructed.  For  the  support  of  the  ante- 
rior end  of  the  bridge,  the  method  hitherto  practiced  has  been 

Pig.  328. 


to  excise  the  crown  of  the  cuspid  and  fit  a  porcelain  crown  with 
gold  backing  to  the  root,  ami  to  this  the  anterior  end  of  the 

1. ridge  is  soldered.       Ur 

"Fig.  329  illustrates  a  device  which  obviates  the  necessity 
for  removing  thej;nspid  crown.  A  gold  band  is  fitted  around 
the  ^nSpid  at  the  "front, ..shown  at  a.  ThiL  band  is  allowed  to 
pass  a  little  beneath  the  margin  of  the  gum,  so  as  to  make 
the  smallest  possible  exhibition  of  gold.      On  the  lingual  aspect 

Fig.  329 


crown. 


h  the  band  is  allowed  to  be  nearly  the  length  of  the 
It  will  be  seen  that,  when  this  band  is  fitted  a*~p©r£ect]y 
as  possible  there  must  necessarily  be  quite  a  vacancy^between 
the  upper  part  of  the  limgual  surface  of  the  tooth  and  the  band. 
It  is  important  that  this  portion  of  the  Viand  tits  the  tooth 
per-foctly,  and  an  accurate  adaptation  is  obtained  as  follows: 
A  piece  of -yery  thin  platinum  or  pure  gold,  rolled  to  No.  35 
American  gauge,  is  fitted  over  that  portion  of  the  lingual  surface 


/C^iu*-^ 


168 


ARTJFI'  l.\L 


-  AND  BRIDGE- WORK. 


of  the  tooth  which  it  is  to  covbr.     d,  Fig.  32!),  shows  the  .-nape 

nrirs.     It  yen  be  perfcetly  lit 
,  with  the  hand  in  position. 

into  the  vacant  space-  hetwcei 

removed  frown  the  tooth 

solder  is  flowed   into 


that  thislitth  -  -tally  as* 

the  use  of  a  burnisher,  and  the] 
of  melted  r£*in  wax  is  flowed 
$««  gold  and  the  hand.     It  i: 
I.  and   atW  nwitin 


Ftq.  831. 


A 


u 


- 


vacancy,  tilling  completely  the  sp^ee  occupied  by  the  wax 

fj>  jA'  the  lingual  portion  v  " 

hmi  it  can  he  ground  or  tile 

now  havy  a  -hand  which 

The  anterior  end  of  the  hi 

the  work  ia  property  tinisl 

Fig 


-be  thicker  than  is  necessary, 

i  6a  the  proper  thickness.     We 

>ortions  of  the  tooth  perfectly. 

soldered  to  this  hand,  and  after 

Mieiitcd  in  place  in  the  ti 

Fio.%8f. 


':  II'!'. 


JynA  ,-.  T/V^^sW  8>de  an- 

.1  geari  S  "  Anchorage  is  formed  as  follows:  From  an 
impression  of  a  natural  crown  taken  in  plaster,  gutta-percha,  or 
raoldine,  a  die  in  fusible' metal  is  formed,  and  from  it  a  counter- 
die  in  lead  is  made.     (8ee"Gtold  Seamless  Cap  Crown.")    On 


j^X^     {^^'i**-* 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK.  1(39 

the  die  a  cntywn  is  stamped  from  a  seamless  cap  of  gold  (Fig.  330). 
This  crownlis  then  fitted  on  the  natural  tooth,  the  labial  aspect 
of  which  islexposed  by  the  removal  of  the  section  of  gold  cover- 
ing it  (Rigsrl&l  aii*l -88*2).  A  shell  for  a  cuspid  can  be  made 
from  a  gold  collar  as  well  as  a  cap.  The  shell  formed  in  either 
manner  is  then  tilled  with  investing  material,  and  strengthened 
by  flowing  20-carat  solder  over  the  surface. 

This  process  for  cuspids  has  decided  advantages  for  the  easy 
tornjation  of  a  perfect-fitting  crown  or  shell  for  bridge-work. 

Fig.  332  shows  the  forms  usually  given  shell  crowns  for 
bicuspids.  When  the  gold  is  removed  at  the  labio-cervical  part, 
the  crown  should  be  additionally  secured  by  a  pin  introduced 
and  soldered  at  the  point  A. 

Fig.  333  illustrates  a  case  in  which  the  lower  incisors  are 
supported  by  shell  crowns  on  the  cuspids. 


Y 


Uhiw-  ■      a  ■ 


WituiL  <^fc  A*^' 


V    * 


•  -*> 
CHAPTER    III. 

EXTENSION    BRIDGES. 


Tins  term  is  applied  to  bridges  which  are  chiefly  supported 
by  one  abutment.  In  relation  to  the  anterior  teeth,  it  consists 
in  attaching  a  dummy  to  an  artificial  crown,  to  replace  an 
adjoining  absent  tooth.  A  bridge  of  this  style  replacing  two  or 
three  of  the  posterior  teeth  is  formed  by  using  two  of  the  teeth 


Fig.  334. 


Fio.  335. 


Fio.  333. 


Fig.  337. 


anterior  to  it  as  one  abutment,  with  a  saddle  for  the  other.  A 
-addle  is  an  oval-shaped  piece  of  gold,  of  the  form  of  the  gum 
and  a  little  larger  than  the  base  of  the  tooth,  placed  under  the 
posterior  tooth  of  the  bridge 

Figs.  334  and  335  represent  an  extension  bridge.     A  crown 

On  the  Cuspid,  an  all-gold   frown   on    the   bicuspid,  and  a  saddle, 

arc  the  abutments.  In  constructing  this  bridge,  the  teeth  form- 
ing the  abutments  were  first  crowned.  The  crowns  were  then 
adjusted  in  position,  and  an  impression  and  articulation  taken  in 

170 


EXTENSION  BRIDG ES. 


171 


plaster,  in  which  the  crowns  were  removed.  From  this  impres- 
sion a  model  was  made  of  plaster  and  marble-dust,  and  an 
articulation  in  plain  plaster.     With  the  crowns  in  position  on  the 


Fig.  338. 


Fig.  330. 


model  as  in  the  mouth,  the  bridge  was  then  constructed  by  the 
methods  described  on   page   156.     The  part  of  the   model   on 


Fig.  340. 


Fig.  341. 


which  the  saddle  rested  was  marked,  and  enough  of  the  surface 
of  the  plaster  removed  to  cause  the  saddle   to   press   tightly 


Ftg.  342. 


against  the  soft  tissues  when  the  bridge  should  be  completed  and 
inserted  in  the  mouth. 

A  shell  crown  on  a  cuspid  can  be  used  as  an  abutment  in  this 


172 


ARTIFICIAL  CROWS-  AXD  BRIDGE- WORK. 


style  of  bridge,  instead  of  excising  the  natural  crown  and  mount- 
ing an  artificial   crown  on  the  root  for  the  purpose  (Figs.  336, 


Fig.  343. 


£8.  338,  339,  340,  and  341  represent  small  extension  bridges 
of  frequent  construction,  and  Fig.  342  a  pin-shell  crown  which 

Fig.  344.  Fig.  345. 


can  be  made  to  support  a  porcelain  front   representing  a  cuspid 
or  bicuspid. 

14,  and  345  represenl  an  extension  bridge  con- 


EXTENSION  BRIDGES. 


173 


Btructed  by  Dr.  II.  A.  Parr,  of j  New  York.  The  anterior  abut- 
ment consists  of  the  six  front  tieth,  which  were  all  crowned  and 
joined  together,  the  pulps  being  preserved  in  the  incisors.  A 
saddle  on  each  side  forms  the  posterior  abutments. 

A  Spur  Support  consists  of  a  flange  formed  at  the  end  of  an 
extension  bridge,  .affording  support  by  resting  on  the  palatal 
wall  of  either  an  incisor  or  cuspid,  or  in  the  sulcus  between  the 
•  usps  of  a  bicuspid  or  molar.  f-Fig.  346  illustrates  a  case  with  a 


Fig.  348. 


Fig.  349. 


spur  resting  against  a  cuspid.  In  the  case  represented  in  Figs. 
347  and  348  the  spur  rests  in  an  indentation  in  an  amalgam  till- 
ing in  the  molar,  and  is  termed  a  cantilever  bridge.     A  bridge 


CHAPTER    IV. 

DorRbK     BAR- BRIDGES 


In  this  style  of  bridge  the  teeth  ojxtummies  forming  it  are 
supported  by  bars  anchored  by  tiTLkTgs  in  the  natural  teeth  form? 
in"-  the  abutments.  Its  use  isVonfined  to  the  insertion  of  one  or 
two  teeth.  ?  Ija_the  incisors  and  cuspids  the  cavities  of  anchorage 
are  formed  in  the  palato-approximal  portion  of  the  teeth  con 
ois  to  the  space  to  be  bridged,  about  one-third  of  an  inch 
from  the  gingival  margin  (Fig.  350),  and  having  direct  ^access  \ 
into  a4-4*«*t-aue-of  the  cavities  through  the  palatal  wall. 

In  constructing  tin- 
is 


"' 
U 


constructing 
first    made.-    Irid 
about  No.-i*~to  No 


bridge  the  bar 
^-platinum    wire 


16  T.  S.  standardl  | 
gauge  is  preferably  used  for  the  pur- 
pose. The  extremities  are  formed 
square  or  triangular,  increasing  m  size 
towards  each  end,  and  fitted  deep  into 
the  cavities  of  the  teeth  which  are  to 
support  them.  The  bar  is  then  adjusted 
and  a  suitable  plate  tooth  ground  and 
fitted  in  proper  position  against  it, — a 
portion  of  the  labial  surface  of  the  bar  being  removed  to  receive 
it.  The  tooth  i-  then  backed  with  very  thin  platinum,  cemented 
with  wax  to  the  bar,  and  the  tooth  and  bar  removed,  invested, 
and  Boldered.,  Suflicient  gold  should  be  added  to  properly  contour 
the  part  (A,  Kig.  3501,  [Gold  and  armdgam  arc  the  only  filling- 
materials  suited  lor  awekomi^  oi  tin-  character.  Amalgam 
i-  objectionable  only  when  the  position  of  the  cavity  renders  it 
visible.  It  can,  however^  when  set  be  partially  removed  at  the 
exposed  portion  and  covered  with  gold.     Fastening  one  end  of 

the   bar   temporarily  with  oxyphosphate  while  the  other  is  being 
cured,   will   sometimes   facilitate  the  operation  of  anchoring.  * ' 
luently  in  the  bicuspids  and  molars  it  is  advantageous  to  drsl 


DOUBLE  BAR-BRIDGES. 


175 


insert  one  or  both  of  the  fillings,  and  then  drill  out  sufficient  of 
it  to  admit  the  bar,  which  can  then  be  secured  with  additional 
filling-material.  When  gold  is  the  filling-material. used,  the 
rubber-dam  is  first  adjusted  on  the  natural  teeth  a-*td  the  bridge 
placed  in  position  over  it. 

The  practical   |uceess  of  this  style  of   bpidjgc^work  depends 

clrefly  upon   the  character  of  its  supports  and  the  skillfulness 

th  which  it  a  anchored.  "mm    ^C 

.1   Bar-Bridge  with  a  Detuchabl    Porcelain  Front  affords  access 

to  the  cavities  of  anchorage  and  admits  of  replacement  of  the 

porcelain  in  case  of  fracture. 


-& 


A  modification  of  Dr.  I.  F.  WardwelFe  method,  which  is 
simple  in  construction  and  application  in  comparison  with  most 
forms  in  use,  is  as  follows :    A  thick,  narrow   piece  of  18-carat 

Fig.  352.  Fig.  353.  Fig   354. 


Fig.  351. 


gold  plate,  at  least  No.  18  standard  gauge,  is  soldered  to  the 
tooth  and  its  two  sides  undercut  with  a  very  thin  separating  file 
(Figs.  351,  352).  A  very  thin  piece  of  platinum,  covering  the 
whole  back  of  the  tooth,  is  then  burnished  against  it,  well  into  the 
undercuts,  the  platinum  beiug  annealed  several  times  during  the 
operation.  The  platinum  is  next  held  in  a  flame  while  a  small 
quantity  of  pure  gold  is  flowed  over  the  outer  surface  and  then 
refitted  to  the  back  of  the  tooth,  to  which  it  is  again  burnished. 
This  operation  is  repeated  until  the  platinum  and  gold  form  a 
moderately  light  backing  which  fits  perfectly.  The  platinum 
surface  is  then  covered  with  investing  material,  and  on  the  other 
side  18-  or  20-carat  gold  plate  is  flowed  until  a  suitable  thickness  is 
obtained.  When  trimmed  into  proper  shape  and  attached  to  the 
bar,  this  forms  a  substantial  backing  or  socket  (Fig.  353)  iu  which, 
when  the  bar  is  anchored,  the  porcelain  tooth  can  be  fastened 
with  a  little  oxyphosphate  cement  or  gutta-percha  (Fig.  354). 


'V 


I" 


17f,  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

The  Low  porcelain  front  consists  of  a  porcelain  facing  which 
fits  into  a  metallic  socket,  where  it  is  retained  by  grooves  on  the 
Bides.  The  metallic  part  is  soldered  in  position  and  the  porcelain 
font  cemented  on.  (See  page  126.) 
Fiff.  355  represents  a  double  bar-bridge  formed  with  an  all- 
ar  crown.   'Z/.jls 


gold  HK>] 


simethod  of  constructing  a  dandle  bar-bridge 
with  a  removable  molar  or  dummy  is  as  follows: 

The  bar  is  formed  as  seen  in  Fig.  356.  A  countersunk  molar 
is  ground  and  shaped  as  seen  at  A  and  B,  Fig.  357.  To  the  base 
of  the  molar  and  up  in  the  slot  is  shaped  and  fitted  the  shell  0, 


Fio.  355. 


Fig.  356. 


Fig.  357 


Fig.  358. 


made  of  a  very  thin  piece  of  gold  and  platinum  crown-metal  by 
first  stamping  it  on  a  fusible  metal  die  of  the  base  and  then 
adapting  it  to  the  part.  A  thin  piece  of  clasp-metal  (D)  is  then 
formed  to  fit  over  the  bar  and  in  proper  position  into  the  slot  of 
the  shell  (C,  Fig.  356),  to  which  it  is  soldered  by  investing  and 
Boldering  from  the  inside  of  the  shell.  The  shell  is  then  cemented 
with  oxyphosphate  onto  the  base  of  the  molar  as  seen  at  A  and  B, 
Fig.  356,  and  is  secured  to  the  bar  by  springing  together  the  edges 
of  the  metal  at  C.    Fig.  358  illustrates  the  bridge  in  position. 


CHAPTER  V. 

EXTENSIVE    APPLICATIONS    OF   CROWN-   AND    BRIDGE-WORK. 

The  following  illustrations  of  bridge-work  by  Dr.  H.  A.  Parr, 
of  New  York,  show  to  what  an  extent  the  system  can  be  applied. 


Fig.  359. 


Fig.  360. 


Figs.  359,  360,  361,  and  362  represent  a  case  in  which  the 
roots  of  the  two  superior  centrals,  a  partially  decayed  right  first 
molar,  and  a  badly  decayed,  pulpless  left  first  molar  were  all  that 

12  177 


178 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


remained  of  the  upper  natural  teeth.     On  the  two  central  roots 
were  mounted  collar  crowns,  and  on  the  two  molars  all-gold 

Fig.  361. 


Fig.  362. 


•cap  crowns.     These  four  crowns,  acting  as  abutments  for  the 
dge   denture,   l»orc   between   them,  proportionately  on   each 


EXTENSIVE  CROWN-  AND  BRIDGE- WORK. 


179 


side,  the  force  and  leverage  of  occlusion.     The  contour  of  the 
arch  in   the  region  of  the  cuspids  was  restored  by  a  skillful 

Fio.  364. 


Fig.  366. 


and  artistic  placing  of  the  artificial  teeth,  which  are  prominent 
and  Ion 2". 


180 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  368. 


Fig.  369. 


EXTESSIYE  CROWN-  AND  BRIDGE-WORE. 


181 


Figs.  363,  364,  365,  and  366  represent  a  case  in  which  two 
large  and  firm  superior  cuspid  roots,  and  a  right  pulpless  molar, 
with  a  saddle — an  invention  of  Dr.  Parr's — on  the  left  side  sup- 
port a  large  bridge. 


Fm.  370. 


In  the  bridge-work  illustrated  in  Figs.  367,  368,  and  369, 
crowns  on  a  second  bicuspid,  a  pulpless  molar,  and  the  roots  of  a 
cuspid  and  lateral  constitute  the  abutments. 

Fto.  371. 


Figs.  370  and  371  illustrate  an  extensive  case  of  artificial 
replacement  by  crowning  and  bridging  operations.  Fig.  370 
represents   the    case    as   presented    for    treatment.      The   few 


1-2 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 
Fig.  372. 


Fig.  373. 


EXTENSIVE  CROWN-  AND  UlUDOI.-WORK. 


183 


remaining  superior  and  inferior  natural  teeth  had  no  corre- 
sponding antagonists,  which  caused  the  interlocking  and  abnor- 
mal condition  in  regard  to  occlusion  shown.  The  superior 
right  bicuspid,  the  left  central,  and  the  left  cuspid  were  crowned, 


Fig.  374. 


the  bicuspid  being  shortened  and  the  cuspid  lengthened  in  the 
operation.  The  intervening  lateral  root  between  the  central 
and  cuspid,  having  been  treated  and  tilled,  was  allowed  to 
remain.      "With  the  three    crowns  to   serve   as  abutments  the 

Fig.  375. 


intervening  spaces  were  bridged  with  artificial  teeth,  the  exten- 
sion on  the  left  side  being  supported  by  a  saddle.  The  spaces 
between  the  inferior  cuspids  and  molars  on  both  sides  were 
bridged,  the  bicuspid  on  the  left  supporting  the  bridge,  instead 


1 84  - 1  R  TIFU  'IAL  <  1(0  WN-  A  ND  BRIDGE-  WORK. 

of  the  cuspid,  as  on  the  right;  the  left  cuspid  was  crowned  and 
the  incisive  edges  of  the  incisors  trimmed  even. 

Fig.  371  illustrates  the  case  finished  and  shows  the  complete 
artificial  restoration  of  the  parts. 

Pigs.  372  and  373  represent  a  case  in  which  crown-  and  bridge- 
work  has  been  extensively  applied.  The  occluding  surfaces  of 
the  teeth  were  affected  with  abrasion.  Gold  crowns  with  porce- 
lain fronts  which  presented  laterally  the  form  illustrated  were 
mounted  on  the  incisors  and  cuspids,  the  pulps  of  which  were 
preserved.  The  posterior  teeth  were  crowned  with  all-gold 
crowns.  The  missing  teeth,  except  those  on  the  inferior  left 
.-ide,  were  artificially  restored  with  bridge-work. 

In  the  case  illustrated  by  Figs.  374  and  375,  two  superior  mo- 
lars and  a  second  bicuspid  on  the  right,  and  a  first  bicuspid  and 
a  saddle  under  the  "dummy"  representing  the  first  molar  on 
the  left  side,  form  the  abutments.  This  piece,  at  the  time  of 
"•rJtirrjj^t^'T  K^"-:  ""■■■■  .--atisfaotorily  fcf  five-years.  Prior  to 
the  insertion  of  the  bridge-work,  the  patient  had  worn  artificial 
teeth  on  a  plate. 


/fat  ibx.  -&***.  rf  ^  teGzu^<^ 


CtC^     (la 


■ 


a  '  J  M 


C  II  A  P  T  E  R 


CLl^^Ci  r 


r-    au^ 


Fig.  376. 


REPAIR   OF   CROWN-   OR    BRIDGE-WORK. 

The  fracture  of  a  porcelain  front  to  a  permanently  attached 
bridge  is  an  annoying  accident  for  both  patient  and  dentist.  It 
is  usually  attributable  to  failure  to  properly  protect  the  incisive 
edge  or  occluding  surface  of  the  porcelain  with  metal,  a  precau- 
tion rendered  necessary  by  the  rigid  character  of  the  resistance 
offered  the  antagonizing  teeth  through  the  abutments.  In  most 
cases  the  porcelain  can  be  replaced  without  the  removal  of  the 
bridge,  but  the  attachment  is  not  usually  so  reliable  as  in  the 
original  piece.  The  following  is 
the  method  usually  adopted  with 
incisors  or  cuspids  :  The  surface  of 
the  backing  to  the  porcelain  is 
trimmed  level,  the  platinum  pins 
drilled  out,  and  the  holes  slightly 
countersunk  on  the  palatal  side. 
A  tooth  similar  to  the  one  frac- 
tured, with  long  pins,  is  ground 
and  fitted  to  the  backing.  /  The 
pins  are  then  riveted  on  the  palatal 
side,  into  the  countersunk  holes  of 
the  backing.  The  riveting  is  best 
done  with  punch  forceps  having 

a  large  punch,  the  porcelain  front  being  protected  by  a  piece  of_ 
lead  placed  against  the  labial  aspect  (Fig.  376.)  The  heads  of 
the  pins  should  then  be  burnished  smooth  with  a  revolving 
burnisher.  In  case  of  the  fracture  of  the  porcelain  front  of  a 
bicuspid  crown  or  dummy,  a  corresponding  front  is  selected  with 
very  long  pins,  and  ground  to  fit.  Holes  are  drilled  in  the  gold, 
in  proper  positions,  to  receive  the  pins  their  full  length.     The 

185 


186  ARTIFICIAL  CROWN-  AXD  BRIDGE- WORK. 

pins  are  then  roughened  a  little  with  a  sharp  instrument,  and 
pins  and  trout  are  cemented  to  the  gold.  Should  the  holes  ex- 
tend through  the  gold  at  the  palatal  side,  the  cement  and  the 
ends  of  the  pins  should  be  covered  with  gold  foil  or  amalgam. 
W  any  gold  is  presenl  to  protect  the  occluding  edge  of  the 
lain,  it  <hould  be  burnished  against  the  surface, 
ridge-work  can  be  made  with  replaceable  porcelain  fronts 
which  can  be  easily  substituted  in  ease  of  fracture.  A  descrip- 
tion of  their  application  will  be  found  at  page  175. 

[f  the  character  of  the  breakage  is  such  as  will  not  permit  its 
repair  in  the  mouth,  the  bridge  must  be  removed  for  the  pur- 
pose and  then  reinserted.      Under  such  circumstances  the  advan- 
-  nt'  bridge-work  in  a  detachable  form  are  most  evident. 

The  results  following  the  repair  of  single  crowns  in  the  mouth 
will  seldom  repay  the  labor  attending  it. 

Removal  of  Cemented  <\<>irn.<  and  Bridges. — When  it  becomes 
ssary  to  remove  an  artificial  crown,  whether  inserted  singly 
or  as  a  support  for  a  bridge,  incisors  or  cuspids  are  detached  by 
grinding  the  gold  or  porcelain  away  at  the  palatal  section  over 
tin-  post,  which  when  exposed  is  severed,  and  the  attachment  of 
the  cement  broken  up.  The  collar  can  also  be  slit  and  bent 
a-ide  it'  found  necessary.  In  an  all-gold  cap  crown  on  a  posterior 
tooth  a  hole  drilled  in  the  grinding-surface  will  give  access  to  the 
cement,  a  sufficient  quantity  of  which  can  then  be  removed  to 
loosen  the  attachment  ;  or,  the  collar  can  be  divided  and  pried 
up  from  the  root  by  first  making  a  groove  with  a  small  rubber 
and  corundum  disk  and  then  cutting  the  gold  with  a  sharp  in- 
strument. With  care  and  patience  in  the  operation,  the  crowns 
usually  he  injured  beyond  repair, 
gutta-percha  is  the  cemenl  that  has  been  used,  a  hot 
in-trumeiit  can  be  placed  against  the  metallic  part  of  the  crown, 
or  the  crown  Beized  with  the  beaks  of  heated  forceps,  the  gutta- 
percha thereby  softened,  and  the  crown  removed. 


CHAPTER    VII. 

THE   HYGIENIC   CONDITION  OF  THE    MOUTH  AS  AFFECTED  BY 

BRIDGE- WORK. 

The  probable  future  condition  of  a  mouth  in  which  a  piece 
of  bridge-work  is  permanently  fixed  is  a  matter  of  the  deepest 
interest  to  both  patient  and  operator.  There  is  no  valid  reason 
why  an  artificial  structure  in  the  mouth  should  be  more  hurtful 
than  that  which  is  natural,  provided  that  correct  conditions  are 
observed  in  its  construction  and  proper  measures  are  taken  for 
their  maintenance.  The  natural  teeth  demand  care  on  the  part 
of  their  owners,  and  all  forms  of  artificial  dentures  require 
attention  to  secure  their  cleanliness  and  thus  preserve  the  health 
of  the  adjacent  tissues.  What  will  result  from  the  wearing  of 
a  permanently  fixed  bridge  is  almost  wholly  dependent,  in  the 
first  place,  on  the  proper  application  of  principles  and  correct 
formation  in  every  detail  of  construction  of  both  crowns  and 
bridge-work ;  and  in  the  second  place,  upon  the  maintenance  of 
cleanliness.  Neglect  of  a  single  requirement  will  so  far  detract 
from  the  usefulness  of  the  work,  and  may  influence  the  final 
result  disastrously. 

Firm,  properly  selected  abutments  will  not  redeem  incorrect 
conception  or  faulty  construction ;  neither  will  the  best  construc- 
tion remedy  that  which  is  wrong  in  principle  or  application. 
Self-cleansing  spaces,  if  improperly  formed,  have  exactly  the 
contrary  effect  from  what  is  intended,  by  becoming  receptacles 
for  particles  of  food  del  iris,  instead  of  preventing  their  accumu- 
lation. 

Inaccessible  spaces  or  interstices,  which  are  always  apt  to  cause 
uncleanliness,  should  be  avoided.  Continuity  of  structure  of  the 
several  parts  is  also  essential  to  fully  insure  perfect  hygienic 
conditions. 

187 


[88  ARTIFICIAL  CROWN-  AND  BRIDQE-WORK. 

The  health  of  a  mouth  containing  a  piece  of  bridge-work 
constructed  under  these  precautions  can  be  readily  maintained. 
For  this  purpose  a  suitably  formed  brush  and  a  dentifrice  are 
necessary.  Floss  silkvpassed  through  apertures  around  the  necks 
of  erowns,  in  places  out  of  reach  of  the  brush,  and  drawn  along 
the  gum  under  the  bridge,  will  remove  accumulations"  of  debris 
otherwise  inaccessible.  A  solution  m  a  detergent  and  disin- 
fectant mouth  lotion  in  water,  injea^d  with  a  dental  syringe, 
cau  be  used  advantageously  to  wash  out  such  places  and  maintain 
a  healthy  condition  of  the  gums.  In  addition  to  these  measures, 
the  crowns  and  bridge  should  be  thoroughly  cleansed  by  the 
dentist  at  regular  intervals. 

So  cared  for,  a  permanently  fixed  bridge  will  not  militate 
against  the  absolute  wholesomeness  of  the  mouth;  but  it  can 
hardly  be  expected  that  the  insertion  of  bridge-work  will  insure 
a  state  of  the  mouth  which  for  cleanliness  will  be  superior  to  the 
presence  of  the  natural  teeth.  Neglect  on  the  part  of  the  patient 
to  perform  such  duties  as  are  necessary  to  preserve  the  natural 
teeth  in  a  healthy  state  will  have  about  the  same  effect  on  an 
artificial  denture.  The  attention  required  to  be  given  to  bridge- 
work  is  not  greater  than  is  commensurate  with  the  advantages 
which  it  confers  on  the  wearer. 


CHAPTER    VIII. 

DETACHABLE    AND    REMOVABLE.  BRIDGE-WORK. 

The  evident  advantages  of  bridge-work  have  stimulated  the 
inventive  genius  of  dental  mechanists  to  improve  the  method 
and  form  of  its  construction  and  to  extend  its  application. 
With  these  objects  in  view,  some  bridges  have  been  made  so  as 
to  be  easily  detachable  by  the  dentist,  and  others  removable  by 
the  patients  themselves. 

The  construction  of  bridge-work  in  either  of  these  forms 
overcomes  the  chief  objections  to  the  system.  Large  bridges 
are  much  more  easily  made  in  a  detachable  or  removable  form 
than  are  the  smaller  pieces,  which  present  some  of  the  best 
features  of  the  permanently  attachedimet^hods. 

ThA     tV>H0Wl"ff    In^nTnni^lj    onnntnnnfnrl     frrirlnrnc     timH     carru     ffQ 

illustrate  some  of  the  more  valuable  detachable  and  removable 
methods. 

DR.   WINDER'S    SECTIONAL    CROWN    METHOD; 

This  method,  an  invention  of  Dr.  R.  B.  Winder's,  of  Balti- 
more, presents  the  novel  feature  of  constructing  the  crowns  and 
forming  the  abutments  in  sections,  the  bridge  being  attached  to 
the  detachable  section. 

Fig.  377. 


m 


Fig.  377  illustrates  a  ease  of  bridge-work  made  in  this  manner. 
The  collar  section  of  the  artificial  crown  is  capped  and  cemented 
on  the  natural  crown  or  root,  the  gold  forming  the  occluding 

189 


190 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


portion  of  the  crown,  when  the  bridge  is  adjusted  in  position, 
being  Becured  to  it  with  a  screw.  The  screw  may  be  made  to 
enter  the    body  of   the    crown   as  in  Fig.   378,  or  it  may  be 

Fig.  378. 


Fig.  379. 


Fio.  380. 


Fig.  381. 


soldered  to  the  cap  on  the  collar,  passing  through  the  occluding 
section  of  the  crown,  and  being  secured 
by  nuts  on  the  screws  (Fig.  379). 

When  incisor  or  cuspid  roots  form  the 
abutments,  Dr.  Winder  first  forms  a  cap 
for  the  end  of  the  root,  to  which  a  tube 
is  attached  extending  up  the  root-canal  as 
seen  *fr+gtmm  Fig.  380.  On  this  cap  is 
mounted  the  crown  (B),  the  post  of  which 
fits  the  tube  tightly.  To  the  crown  so 
formed  (Fig.  381)  the  bridge  is  joined  in 
the  usual  manner. 

In  constructing  a  bridge  of  this  style, 
the  crowns  forming  the  abutments  having 
first  been  made,  are  removed  from  the 
month  in   a    plaster  impression   and  articulation,  from  which  a 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  \\)\ 

model  is  made,  showing  the  crowns  in  position.  Each  section 
of  the  bridge  between  the  crowns  is  then  constructed,  and  the 
crowns  adjusted  in  the  mouth.  The  bridges  are  next  inserted  in 
position,  and  cemented  with  resin  and  wax  to  the  detachable 
sections  of  the  crowns.  The  whole  is  then  removed  in  investing 
material,  in  an  impression-cup,  or  by  placing  the  investing  material 
in  position  on  the  bridge.  After  being  removed  from  the  mouth 
more  investing  material  is  added  and  the  bridge  and  crown 
sections  soldered  together.  Only  the  detachable  sections  of  the 
crowns  should  be  in  the  investment  at  the  time  of  soldering. 

The  incisive  edges  can  be  protected  and  the  occluding  surfaces 
of  the  .porcelain  capped  with  gold  as  in  permanently  attached 
bridge-work,  or  they  can  be  formed  of  the  porcelain,  which  latter 
lessens  the  labor  of  construction,  as  the  bridge  is  easily  detached 
from  the  abutments  for  the  purpose  of  repair.  When  the 
occluding  surfaces  of  bicuspids  or  molars  forming  the  bridge 
are  to  be  capped  with  gold,  the  collar  sections  alone  are  first 
made  and  removed  in  the  impression.  The  caps  for  the  crowns 
and  the  bridge  teeth  are  then  formed  of  one  continuous  piece 
of  gold  plate.  This  is  made  by  laying  the  strip  of  gold  on  a 
piece  of  lead  and  stamping  along  its  length  with  suitable  dies 
representing  the  occluding  surfaces  of  the  different  teeth.  The 
gold  is  then  properly  fitted  to  the  collar  sections  on  the  model, 
conforming  to  the  occlusion  of  the  antagonizing  teeth.  The  cusps 
are  filled  with  solder,  and  the  porcelain  fronts,  backed  with  plat- 
inum plate,  leaving  the  pins  straight,  are  fitted  in  position  to  the 
gold  forming  the  caps  and  the  backings,  and  cemented  with  wax. 
The  porcelain  fronts  are  next  removed,  without  removing  the 
backings,  which  are  invested  and  soldered  FlG  3g9 

to  the  caps.  When  this  is  completed,  the 
holes  in  the  backings  are  deepened  with  a 
drill,  and  the  pins  of  the  porcelain  fronts,  hav- 
ing first  been  slightly  serrated,  are  cemented 
in  position  with  oxyphosphate.  This  method  avoids  all  danger 
of  fracture  of  the  porcelain  in  soldering.  Fig.  382  illustrates  its 
application  to  a  single  crown.  When  the  bridge  is  finished  the 
root  and  collar  section  of  each  crown  is  first  cemented  on  in 
position   in  the  mouth ;  the  surface  of  the  detachable  section 


192  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig   383. 


Fio.  384. 


of  the  crown  approximating  the  section  fastened  to  the  bridge 
is  then  heated  and  its  surface  covered  with  a  mere  film  of  gutta- 
percha. The  bridge  is  then  adjusted  in  position  and  secured  by 
the  screws  or  nuts.  The  gutta-percha  prevents  the  secretions 
invading  the  interstices  between  the  sections  of  the  crown. 

Fig.  383  illustrates  another  method,  dk\  ised  by  Di.  J.  II.  Sharp, 
of  constructing  the  sections  of  the  crowns  in  this  style  of  bridge- 
work.     The  part  A  slides  in  the  groove  B.     The  dovetail  flange 

A  is  made  of  a  thick  piece  of  plate, 
fitted  to  the  groove  B,  and  riveted  to 
a  piece  of  platinum  adapted  trans- 
versely across  the  cap  and  then  sol- 
dered to  the  removable  section  of  the 
crown.  Fig.  384  shows  the  sections 
of  the  crown  in  position. 

A  decided  advantage  possessed  by 
this  method  of  bridge-work  over  others  is  the  facility  it  affords 
in  practice  for  the  ready  utilization  of  irregular  teeth  as  abut- 
ments, no  matter  how  much  they  converge  or  diverge,  or  lean 
in  or  out  of  the  line  of  the  arch. 


DR.    LITCH'S    METHOD. 

Dr.  Litch's  method  of  constructing  detachable  bridge-work 
consists  in  forming  a  shell  anchorage  over  posts  permanently 
fixed  on  cuspid  roots,  and  anchoring  the  ends  of  the  bridge  with 
bars  in  slots  formed  in  natural  or  artificial  crowns. 

Figs.  385,  386,  and  387  illustrate  a  bridge  similar  to  the  one 
illustrated  in  Fig.  308  with  this  style  of  attachment  applied. 
The  anchorage  for  the  cuspids  is  constructed  as  follows:  The 
root  is  first  cupped  and  pivoted  as  for  a  collar  crown.  On  the 
palatal  portion  of  the  collar  is  soldered  a  flange  (A,  Fig.  388) 
made  of  gold,  No.  16  CJ.  8.  standard  gauge,  beveled  oil'  to  the 
upper  edge  of  the  collar  under  the  free  edge  of  the  gum.  the 
object  being  to  give  a  larger  surface  to  the  top  of  the  cap.     On 

this  cap,  which  f>>Y<-i-  the  cud  of  the  root,  the  anchorage  post  15, 

which  ie  formed  of  iridio-platinum  wire.  No.  9  U.  S.  standard 
gauge,  is  soldered,  over  and  back  of  the  pin  (C)  which  enters 
the  root-canal,  30   as   to  allow  room    for  the   porcelain    front    1). 


/* 


. 


/p-CcS-  /ft^: 


DETACHABLE  AND  REMOVABLE  BRIDGE- WORK. 


193 


The  porcelain  front  is  ground  in  proper  position  on  this  cap, 
backed,  attached  with  re -mi  and  wax,  and  removed  with  the  cap. 
The  cap  is  next  invested  in  plaster  to  the  edge  of  the. collar,  and 
a  little  plaster  placed  on  the  labial  aspect  of  the  porcelain  front 


Fig.  385. 


Fm.  380. 


Fio.  387 


Fig. 


in  the  form  of  a  matrix,  so  as  to  allow  the  porcelain  to  be 
removed  and  replaced.  A  piece  of  heavy  iridio-platinmn  plate 
(E),  No.  16  U.  S.  standard  gauge,  is  then  shaped  into  the  form 
of  a  half-ring,  with  the  ends  of  the  plate  against  the  backing  of 

13 


194  ARTIFICIAL  CROWN-  AND  BRIDQE-WORK. 

the  porcelain  front,  and  of  sufficient  size  to  rest  on  the  flanged 
edge  of  the  cap  when  completed.  On  the  outside  of  this  half- 
ring  is  fitted  and  soldered  a  thin  strip  of  gold,  F,  of  No.  28 
U.  S.  standard  gauge,  which  will  cover  the  half-ring  and  extend 
beyond  its  cervical  margin,  slightly  overlapping  the  flange  of  the 
collar  (G).  This  forms  a  hrace  or  edge  on  the  anchorage  cap  as 
it  rests  on  the  root-cap.  The  half-ring  is  then  fitted  to  the  tooth, 
attached  with  wax,  and  removed  with  the  tooth  out  of  the  plaster 
matrix  from  the  root-cap,  invested,  and  securely  soldered  on  the 
inside  to  the  hacking  of  the  tooth.  The  tooth  and  half-ring  are 
then  adjusted  to  the  root-cap,  over  the  post  of  which  the  ring 
must  slide  easily  (Fig.  389).  To  this  ring  the  bridge  is  soldered 
the  same  as  to  a  crown. 
„  389  When  the  bridge  is  inserted,  the  cap  for  the  root,  with 
the  post,  is  first  cemented  on  with  oxyphosphate.  After 
the  cement  has  set,  the  anchorage  ring  is  filled  with  more 
cement  and  pressed  into  position  upon  the  cap  over  the 
anchorage  post.  The  surface  of  the  cement  (PI,  Fig. 
388)  can  be  protected  by  a  metallic  filling. 

This  form  of  attachment  permits  the  bridge  to  be 
easily  removed  by  affording  access  to  the  cement  around 
the  pin.  The  bar  ends  of  the  bridge  are  anchored  in 
the  crowns  with  gold  or  amalgam  fillings,  which  like- 
wise are  not  difficult  to  remove. 

The  anchorage  cavity  for  a  bar  in  a  gold  crown  for 
use  over  a  tooth  with  a  living  pulp  is  best  made  by 
cutting  out  the  gold  to  the  form  of  the  slot  required,  and  insert- 
ing in  its  place  ;i  piece  of  platinum  of  the  shape  of  the  walls  of 
the  anchorage  cavity.  The  crown  is  then  filled  with  investing 
material,  and  the  metal  forming  the  anchorage  cavity  soldered 
to  the  crown  at  the  edges  of  the  cavity. 

DR.   R.    W.    STARR'S   METHODS. 

Dr.  It.  Walter  Starr,  of  Philadelphia,  gives  the  following 
descriptions  of  his  methods  in  detachable  bridge-work: 

•■'I'll.'  .•;!-<•  of  Mr.  \V.  presented  difficulties  of  an  unusual 
character,  as  may  be  seen  by  inspecting  the  illustration, -Fig.  390, 
which  renders  detailed  description  unnecessary. 

i 


DETACHABLE  AND  REMOVABLE  BRIDGE- WORK. 


195 


"  It  will  be  observed  that  the  molars  and  the  left  second  bicuspid 
overhang  to  a  degree  that  would  make  the  taking  of  an  accurate 
impression  by  ordinary  methods  well-nigh  impossible.  After  a 
careful  study  of  the  case,  it  was  decided  that  two  separate  pieces 
of  detachable  bridge-work  should  be  attempted,  and,  as  an 
essential  preliminary  step,  the  overhanging  sides  of  the  molars 
and  bicuspids  were  ground  with  engine  corundum-wheels  and 
points  until  those  sides  were  made  much  less  inclined,  when 
plaster  impressions  were  taken,  first  of  one  half,  and  then  of 

Fig.  390. 


the  other  half,  of  the  jaw.  Gold  cap  crowns  were  closely  fitted 
over  the  molars,  left  second  bicuspid,  right  first  bicuspid,  and 
cuspid  stump.  Gold  crowns  were  made  to  telescope  over  all  the 
caps,  which  were  then,  by  means  of  oxyphosphate  cement,  fixed 
firmly  on  the  teeth.  Suitable  plate  teeth  were  selected,  fitted, 
backed,  and  hard-waxed  in  place  between  the  telescoping 
crowns.  After  hardening  the  wax  with  cold  water  from  a  tooth- 
syringe,  the  pieces  were  carefully  removed,  invested,  and  sol- 
dered. The  two  completed  bridges  were  easily  replaced  on  or 
removed  from  the  supporting  capped  teeth,  and  their  appearance 


196 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


when  detached  is  correctly  shown  by  the  illustration,  Fig.  391, 
which  also  shows  the  capped  teeth  and  stumps.  The  figure  like- 
wise shows  the  results  of  the  novel  method  employed  in  crown- 
ing  the  incisors.  Gold  collars  were  fitted  tight  on  the  necks  of 
the  incisor  stumps,  and  the  new-style  porcelain  caps  adjusted  in 
the  collars,  and  set  in  the  oxyphosphate  cement  which  had  been 
packed  into  the  collars  ;  thus  at  the  same  time  fastening  the 
collars  on  the  stumps  and  the  caps  in  the  collars,  as  shown 
completed  in  Figs.  391  and  392. 


Fig.  391. 


'•  Fig.  392  illustrates  the  finished  crowns  and  bridges,  which 
latter  were  Becured  in  position  by  placing  a  small  piece  of  gutta- 
percha  in  <-a<-li  of  the  telescoping  cap  crowns,  which  were  then 
warmed  and  carefully  pressed  in  pla<-e, — the  gutta-percha  filling 
only  the  spaces  between  the  flat  tops  of  the  caps  of  the  natural 
teeth  and  cusped  caps  of  the  brid. 


DETACHABLE  AND  REMOVABLE  BRIDGE- WORK. 


197 


"•  Whenever,  for  repair  or  for  any  other  purpose,  it  shall  be- 
come desirable  to  remove  one  of  the  bridges,  that  may  readily 
be  done  by  applying  a  hot  instrument  or  hot  air  to  the  caps  to 
soften  the  gutta-percha  sufficiently  to  permit  the  telescoping 
bridge  to  be  taken  off. 

"  A  full  upper  vulcanite  denture  was  made  to  replace  the  old 
one,  which,  by  improper  occlusion,  had  thrown  the  full  force  of 
mastication  on  the  anterior  teeth  of  the  lower  jaw,  and  produced 


Fig.  392. 


Fio   393. 


the  destructive  action   that  resulted  in  the  deplorable   loss  of 
tooth-substance  shown  in  Fig.  390."  * 

The  next  case  also  presented  unusual  difficulties.  "  The  forward 
overhang  of  the  inferior  right  second  molar  was  so  excessive  that 
an  impression  could  hardly  be  taken,  until  with  corundum-wheels 
and  points  the  sides  of  the  tooth  had  been  made  parallel,  or 
rather  slightly  tapering  to  form  a  truncated  cone,  with  the  neck 
as  a  base.  The  molar  was  alive  and  sound,  but  the  crown  was 
gone  from  the  pulpless  cuspid,  which  I  suitably  shaped  by  means 
of  my  root-trimmers  (Fig.  393). 

1  Dental  Cosmos,  vol.  xxviii,  No.  1,  page  17. 


198 


ARTIFICIAL  CROWX-  AND  BRIDGE- WORK. 


"'An  impression  was  then  taken,  the  cast  from  which  is  illus- 
trated by  Pig.  394.  A  seamless  gold  collar  was,  by  means  of  a 
slightly  tapering  mandrel,  made  to  exactly  lit  the  tapered  natural 
molar,  the  lower  edge  of  the  collar  cut  to  conform  to  the  gin- 
gival margin;  a  cap  piece  of  gold  plate  soldered  to  the  top  edge 
of  the  collar,  and  a  hole  drilled  through  the  center  of  the  com- 
pleted  cap  (A,  Fig.  394).  Care  was  taken  to  so  fit  and  proportion 
the  cap  that  it  would  require  finally  pretty  hard  driving  to  send  it 
h<  mie  i  >n  the  tooth  ;  but  first  there  was  fitted  to  the  cap  a  telescop- 
ing seamless  collar,  on  which  was  soldered  a  gold  plate,  with  cusps, 

Fig.  394. 


to  form  a  molar  crown  as  shown  in  Fig.  394.  The  molar  was 
then  thoroughly  dried,  slightly  painted  with  Agate  cement,  and 
the  cap,  A,  driven  hard  down  with  a  fiat  pine  stick  held  upon  it 
and  -truck  with  a  mallet;  the  hole  in  the  cap  enabling  me  to  see 
when  the  cap  was  quite  down.  The  cuspid  was  then  likewise 
fitted  with  ;i  seamless  gold  collar,  the  top  edge  <>f  which  was 
given  a  roof-shape,  as  seen  above  the  root  in  Fig.  394.  A  piece 
of  gold  received  a  corresponding  roof-shape,  had  a  short  section 
'■I'  gold  tubing  soldered  into  it,  and  was  trimmed  to  the  outline 
of  the  collar,  beside  which,  I'.,  Fig.  394,  its  form  is  seen,  and  to 
which  it  was  subsequently  soldered,  after  suitable  investment  to 
keep   the  parts   in    proper  place.      The   root-canal  had  been  pre- 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


199 


viouslv  prepared  to  receive  the  tube,  which,  with  its  roofed  cap, 
was  with  stick  and  mallet  driven  hard  down  over  the  root.  A 
piece  «>t'  gold  wire  exactly  fitting  the  tube  had  a  roof-shaped 
piece  of  properly-perforated  gold  plate  slipped  over  it  into  posi- 
tion on  the  root;  became  fixed  in  such  relation  by  a  drop  of 
melted  hard  wax;  was  removed,  invested,  soldered,  and  finished 
in  such  shape  that,  excepting  the  hollowness,  it  looked  like  the 
tube  and  cap  B. 

"  The  relations  of  the  occluding  teeth  had,  of  course,  been 
determined  by  an  articulating  model,  and  by  means  of  it  a  series 
of  seamless  gold  collars  and  cusp-crowns  were  adjusted  on  a  thin 
platinum  plate  fitted  on  the  cast  between  the  cuspid  and  second 
molar,  and  the    collars  soldered  to  the  plate  after  investment. 


Fig.  395. 


The  truss  thus  formed  received  an  appropriate  finish  by  the 
rounding  and  smoothing  of  its  basal  borders.  A  plain  plate 
cuspid  was  backed  with  gold  plate  and  fitted  on  the  roof-plate,  to 
which,  after  determining  its  proper  occlusion,  it  was  secured  by 
hard  wax;  removed,  invested,  and  soldered.  It  was  then  put 
into  the  tube  on  the  root;  the  telescoping  cap  put  over  the  molar; 
the  truss  put  in  position  in  the  mouth,  and  the  whole  covered 
with  plaster  and  marble-dust,  contained  in  a  suitable  sectional 
impression-tray,  which  enabled  me  to  hold  the  mass  steadily  in 
place  until  the  mixture  was  sufficiently  hard  to  bring  away  cap 
and  truss  and  roof-plate  all  in  proper  position.  A  second  mixture 
of  plaster  and  marble-dust,  and  a  suitable  trimming  of  the  first 
mixture  after  all  was  hard,  sufficed  for  the  soldering  process  thai 


200 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  3%. 


resulted  in  the  denture  which,  when  finished,  appeared  as  shown 
detached  at  C,  Fig.  394,  and  mounted  on  the  cast  in  Fig.  395.  It 
went  firmly  to  place  in  the  mouth,  and  yet  was  removable  in  the 
possible  event  of  accident  to  the  denture,  or  for  readjustment  of 
the  eusp-erowns,  which  latter  could  easily  be  done  by  warming 
the  piece  sufficiently  to  soften  the  gutta-percha,  replacing  the 
denture  on  its  anchorages,  and  directing  the  proper  closure  of 
the  occluding  teeth. 

DR.  C.  M.  RICHMOND'S  METHOD. 

"  Dr.  C.  M.  Richmond,  of  New  York  City,  iii/Hiaking  remov- 
able dentures  of  the  entirely  soldered  kind,  employs  a  zinc  die 
made  from  a  Cast  of  the  anchor  tooth  wmi  its  cap  on.  He 
makes  of  crown-tnetal  (platinum  faced  wmi  gold)  a  collar/some- 
what smaller  than \he  tooth-cap,  and  ch?ep  enough  to  reach  from 
the  gum  to  about  a  sixteenth  of  an  inch  above  the  cap, '  He  then 

he  die  into  the  collar  so  far 
aj/the  extra  sixteenth  of  an  inch 
be  hammered  over  and  burnished 
on  the  die-end  to  form  a 
collar/  Outside  \£  this,  in 
the  same  manner,  he  forms  another 
flanged  collar,  and  then  solders  the 
two  together,  thus  obtaining  a  6k>se- 
fitting,  stiff  collar,  that  will  fwt 
stretch  it/being  telescoped  on  and  off  the  anchorage,  and  is  keptN 
by  the  flange  from  being  forced  too  far  over  the  tooth-cap.  A 
denture  of  this  kind  is  illustrated  in  Fig.  396,  which  also  shows 
his  j.ost  and  roof  device  in  another  form  than  that  previously 
described." ' 

DR.    PARR'S    METHODS. 

Detachable. — Fig.  397  illustrates  a  method  of  this  Btyle.  The 
teeth  forming  the  abutments  lean  toward  each  other  posteriorly 
and  anteriorly  over  the  space  to  be  bridged,  as  shown  on  the 
original  model.  Pig.  398.  The  bridge  is  supported  by  two 
shoulders  on  the  abutraenl  crowns,  which  slide  into  grooves 
formed  in  the  dummies  (Fig.  399).     These  supporting  shoulders 

1  Dental  Cosmos,  vol.  xxviii,  No.  8,  pHge  497. 


_  ^7  &-  ln-i^Ly^     &r»AX<7Vt  tL^C 


*—  i  ■  -      „  ~*~Tr~ trrfm^T— *^H 


DEWAVHAbLE  AND  REMOVABLE  BRIDGE- WORK.  201 

and  slots  are  made  by  shaping  two  pieces  of  plate  to  the  form 
shown  in  Fig.  400,  so  that  one  shall  telescope  the  other.  The 
inner  one  is  then  invested  on  the  outside  surface  and  filled  in  with 

Fig.  397. 


gold  plate.  The  outer  piece  is  then  filled  inside  with  investing 
material,  and  gold  plate  is  flowed  over  the  outer  surface.  The 
shoulders  are  first  soldered  to  the  crowns,  and  afterward  the 
slots  are  adjusted  to  them  and  soldered  in  position  in  the  bridge. 

Fig.  399. 


Fig.  398. 


QD 


Fig.  4ou. 


Removable  Bridge. — In  this  style  the  crowns  forming  the  abut- 
ments are  permanently  cemented  in  position,  each  section  of  the 
bridge  between  them  being  removable.     The  case  illustrated  in 

Fig.  401. 


D 


Fig.  401  will  serve  as  a  type  to  give  the  constructive  details. 
The  cuspid  and  molar  crowns  are  first  formed  in  the  usual  man- 
ner.    A  model  from  an  impression  is  then  made  on  which  the 


#-& 


■     . 

■ 


ARTIFICIAL  CROWN-  AND  BRIDOE-WORK. 

crowns  will  be  in  the  same  position  as  in  the  mouth.  A  gold 
and  platinum  bar  (A,  Fig.  402)  is  then  formed  between  the 
cuspid  and  molar.  The  end  for  the  cuspid  is  rounded,  and  that 
for  the  molar  flattened.  This  last  may  be  done  by  hammering 
the  wire  flat  or  by  soldering  a  piece  of  clasp  plate  transversely 
to  it.  The  two  ends  of  the  bar  are  then  fitted  in  sockets  of 
platinum  (B,  B).  The  ends  of  the  bar  should  be  bent  and  the 
platinum  sockets  placed  in  such  a  position  against  the  sides  of 
the  crowns  that  the  bar  can  be  easily  adjusted  and  removed. 
The  sockets  are  next  soldered  to  the  sides  of  the  cuspid  and 
molar  crowns  (A,  A,  Fig.  401),  for  which  purpose  the  sockets 
and  crowns  should  be  removed  and  invested.  The  sockets  are 
held  in  position  when  the  wax  is  melted  out  by  pieces  of  iron 
wire,  one  end  of  which  covered  with  a  portion  of  the  investing 
material  is  inserted  in  the  socket,  the  other  end  being  imbedded 
in  the  investment.  If  preferred,  the  slot  on  the  side  of  the 
molar  crown  can  be  made  with  a  piece  of  platinum  adapted  over 
the  Hat  piece  of  gold  forming  the  end  of  the  bar  and  then  sol- 
dering the  platinum  to  the  side  of  the  crown,  the  platinum 
being  stiffened  by  flowing  the  solder  over  it.     At  this  point  the 

crowns  and  bar  may  be  adjusted  in  the 

Fl0-  402'  mouth,  as  well  as  on  the  modei,  to  in- 

B  •  J  [|  g    sure  accuracy.    Apiece  of  thin  platinum 

ri r^        or  gold  is  then  perforated  and  slipped 

'(Ji^        ;  "      -SJ         over  the  ends  of  the  bar,  which  is  placed 
A  in    position    on    the    crowns,    and    the 

platinum  or  gold  adapted  to  the  form  of  the  attachments,  and  to 
the  immediately  adjacent  surfaces  of  the  crowns.  These  shell 
forms  are  made  to  assure  to  the  ends  of  the  bridge  a  perfect  tit  by 
giving  them  the  shape  of  the  crowns  and  the  attachments  on  the 
crowns.  To  this  bar  the  teeth  constituting  the  bridge  are  fitted 
in  their  respective  positions  and  soldered.  Bending  either  end  of 
the  bar  .lightly  (B,  B,  Fig. 401) or  sawing  a  slit  in  the  cuspid  end 
of  it  (Fig.  410),  afford  the  meane  of  holding  the  bridge  firmly  in 
position,  although  it  may  be  removed  and  reinserted  at  the  option 
of  it-  wearer.     Fig.  I";;  shows  the  inserted  bridge. 

Fig.  4ni  showe  another  method  of  forming  a  socket  attach- 
ments    In  tin-  figure,  Hie  socket  section  of  the  attachment  is 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


203 


seen  projecting  from  the  side  of  the  molar  crown.  The  other 
section  consists  of  a  cap  having  a  spring  flange.  The  flange 
enters  the  socket,  which  the  cap  incloses  on  the  top  and  sides. 
The  spring  is  made  by  bending  open  a  little  the  part  of  the 


flange  marked  A. 


Fig.  403. 


Fig.  404. 


This  form  of  attachment  is  constructed  as  follows:  To  make 
the  spring  flange,  two  pieces  of  clasp  or  spring  gold  plate  ahout 
No.  23  U.  S.  standard  gauge,  one  of  them  one-half  and  the  other 
one-fourth  of  an  inch  long  and  from  one-eighth  to  one-quarter  of 
an  inch  wide,  the  exact  dimensions  being  governed  by  the  case  in 
hand,  are  laid  together,  so  that  one  end  of  the  short  piece  is  nearer 
one  end  of  the  larger  piece  than  the  other.  The  edge  of  the  short 
piece  nearest  the  end  of  the  longer  one  is  then  soldered  to  it  with 
a  hard-flowing  solder,  the  two  being  held  during  the  operation  in 
a  blue  gas  flame  with  tweezers,  and 
the  end  is  trimmed  square.  A  little 
whiting  placed  between  them  will  pre- 
vent the  solder  from  flowing  between 
or  joining  them  at  the  other  edge. 
The  short  piece  of  plate  is  to  form 
the  spring,  and  is  left  unconnected 
at  one  end  for  that  purpose  (A,  Fig. 
405). 

To  Form  the  Socket. — The  spring  flange  is  first  enveloped  once 
around  with  a  thin  piece  of  platinum,  a  little  deeper  than  the 
socket  is  required.  The  platinum  is  then  enveloped  with  one 
thickness  of  coin  gold  plate,  No.  32  U.  S.  standard  gauge,  about 
the  depth  the  socket  is  to  be,  leaving  a  ledge  of  the  platinum  pro- 
jecting. The  platinum  and  gold  are  next  removed  and  soldered, 
by  holding  them  in  a  flame  and  using  very  little  solder,  of  a  hard- 
flowing  variety,  which  is  placed  upon  the  ledge.     The  sides  and 


204  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

ends  of  the  socket  are  then  filed  level  and  the  socket  given  a 
Bquare  form  (B,  Fig.  405). 

To  Form  tfu  Cap. — The  spring  flange  having  been  inserted 
in  the  Bocket,  two  pieces  of  the  spring  gold  plate  of  the  same 
length  as  the  socket  are  adjusted  along  its  sides,  the  pieces  being 
cut  a  little  wider  than  the  depth  of  the  socket,  so  that  when 
adjusted  they  shall  project  slightly  above  it.  A  piece  of  thin 
platinum  plate  is  then  adapted  to  the  end  of  the  flange,  to  the 
socket,  and  to  the  pieces  of  spring  plate,  first  being  perforated 
to  allow  the  projecting  ends  of  the  latter  to  pass  through  it.  The 
spring  plates  and  the  flange  plate  are  then  cemented  to  the 
platinum  plate  with  wax,  removed  from  the  socket,  invested, 
and  soldered  (C,  Fig.  405). 

The  sockets  must  be  so  placed  on  the  crowns  that  the  springs 
at  the  ends  of  the  bridge  shall  enter  them  on  parallel  lines. 
Their  proper  relative  positions  to  secure  this  movement  are 
readily  determined  by  attaching  the  tops  of  the  spring  flanges 
(either  temporarily  or  permanently)  to  the  ends  of  a  piece  of 
wire  of  the  length  of  the  space  to  be  bridged,  which  will  permit 
the  necessary  adjustment.  The  sockets  are  then  soldered  onto 
the  crowns. 

When  the  bridge  teeth  or  dummies  adjoining  the  sockets  have 
been  fitted  in  position,  they  are  withdrawn  with  the  caps  and 
spring  flanges,  and  soldered  to  the  bar,  in  the  manner  described 
at  page  202.  The  gold  caps  forming  the  occluding  surfaces  of  the 
bridge  tooth  can  usually  be  fitted  over  the  cap.  When  the 
sock't  is  to  be  attached  to  the  crowns  lengthwise,  as  in  Fig.  401, 
the  spring  metal  plate  is  placed  only  on  the  labial  or  buccal  side 
of  the  socket. 

In  a  bridge  of  this  style  of  the  anterior  teeth  only, — where  the 
abutments  form  the  extremities  of  the  piece, — the  ends  should 
be  attache^  to  the  mesial  sides  of  the  crowns  forming  the  sup- 
ports; but  when  it  als<»  carries  teeth  posterior  to  the  abutment, 
and  the  Sections  of  the  bridge  are  united  together,  the  attach- 
in  -lit  should  be  made  on  the  distal  side,  the  bar  supporting  the 
anterior  teeth  resting  in  a  slot  formed  on  the  palatal  side  of  the 
abutment  (Pig.  406).  A  shell  crown  on  a  cuspid  can  be  utilized 
as  a  -upport  for  this  form  of  attachment. 

/AjLL  r  fr  .-  A  ~a  *  a.  ..    i  A  .    *  m.j       1     I    ( *■  i  . 


c***- 


/  v.-        "uv^JL 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


205 


Fio.  406. 


Fig   407. 


Fig.  407  illustrates  a  removable  cuspid  crown  which  can  be 
used  in  removable  bridge-work.  It  is  Iconstructed  as  follows  : 
The  end  of  the  root  is  first  capped.  VA  porcelain  cross-pin 
tooth,  the  pins  of  which  are  set  well  apart,  is  then  ground  and 
adjusted  in  position,  cemented  with  wax  to  the  cap,  and  both 
removed.  Enough  plaster  to  form  a  matrix  is  placed  on  the 
labial  aspect  of  the  porcelain  and 
collar  to  hold  them  in  relative  posi- 
tion when  the  wax  is  removed.  A 
flat  post  is  then  formed  ou  the  root- 
cap,  extending  from  the  ^3&ial  edge 
forward  between  the  pins  of  the  tooth, 
the  porcelain  of  which,  between  the 
pins,  should  be  slightly  cut  out  to 
receive  it.  To  this  is  soldered  the  piece  A  which  is 
to  act  as  a  spring.  The  post  is  formed  of 'plate,  No. 
18  U.  S.  standard  gauge,  and  the  spring  of  clasp  or 
spring  gold  No.  26.  The  post  is  soldered  to  the  cap 
from  the  opposite  side  to  the  spring  by  investing  with- 
out the  tooth.  The  tooth  is  then  lined  with  very  thin 
platinum  and  with  the  aid  of  the  matrix  is  adjusted 
in  position  on  the  cap,  and  a  thin  piece  of  platinum 
plate  is  slit  at  the  edges  and  adapted  over  the  post,  cap,  and  edge 
of  the  collar,  with  its  inner  edge  meeting  the  backing  of  the  tooth. 
The  platinum  plate  is  then  cemented  with  wax  to  the  backing  on 
the  tooth,  removed  with  it  from  the  cap  and  post,  and  invested, 
the  slot  for  the  post  being  carefully  filled  with  the  investing 
materiah___&«td4iiate  is  then  flowed  over  the  plate  and  backing 
so  as  to  consolidate  the  parts  in  one  piece. 

This  crown  when  finished  will  fit  on  the  cap  and  post,  the 
spring  of  which  can  be  bent  to  securely  retain  it.  The  line  of 
the  spring  post  on  the  cap  as  it  fits  in  the  slot  in  the  crown  should 
be  such  as  will  favor  the  insertion  and  removal  of  the  bridge. 


sT) 


CHAPTER    IX. 


REMOVABLE    PLATE    BRIDGES. 


In  this  style  of  bridge  a  plate  is  used  to  span  t|te  space 
and  support  the  artificial  teeth  between  the  abutmentsy^tX prime* 
requisite  of  removable  plate  bridges  is  that  the  posts  and  collars 
or  any  form  of  attachments  used  shall  move  evenly  on  and  off" 
the  supporting  roots  or  crowns  in  their  adjustment  and  removal. 
To  secure  this,  the  post=£avities  and  crowns  should  be  ..formed 

and  the  gold  crowns  shapexT^©' 
FlG-  408-  that  the  lines  of  the  center  of 

the  cavities  and  of  the  sidea  of 
the  gold  crowns  shall  be  \as 
nearly  as  possible  parallel.  To 
facilitate  the  operation,  posts  of 
wood  or  metal  should  be  first 
accurately  but  loosely  insertec 
in  the  root-can;  Is,  protruding  a\ 
quarter  of  an  inch,  and  an  im- 
pression taken.  On  the  model 
made  from  this  impression  the 
posts  will  be  found  in  position 
as  in  the  month.  The  plaster 
crowns  are  then  trimmed  to  the  required  form.  (Jutta-pereha  or 
impression  compound,  fitted  to  the  model  and  removed  with  the 
pOste  iii  position  in  it.  can  then  be  used  to  guide  the  operator, 
and  gauge  the  preparation  of  teeth  or  roots  in  the  mouth. 


The  case  shown  in  Fig.  40s  will  be  taken  to  describe  the  con- 
structing dctail.-Yoi'  this  class>\o[^Vleutui^s  In  the  root  of  the 
central  ;i  tube  is  inserted,  attai  lied  to  a  cap  on  the  end  of  the 
root.  Over  this  cap  is  placed  an  outer  cap  which  has  a  split 
spring  pivot  or  posl  fitting  the  tube.      A    narrow   plate   between 


^v 


REMOVABLE  PLATE  BRIDGES. 


;the  teeth  connects  the  outer  cap  to 
pests  upon  the  cuspid. 


UJJ^' 


207 


clasp  which  fits  around  and 


he  process  of  construction  is  as  follows, — the  method  being 
similar  when  applied  to  larger  dentures  of  this  class:  The  root 
of  the  central  is  first  prepared  and  capped  the  same  as  for  a  collar 
crown.  The  cap  is  best  formed  ofj/iridio-platinum  plate,  No.  35 
¥■.  6.  standard  gauge  (A,  Fig.  409).  A  substantial  piece  of  gold 
and  platinum  wire,  from  No.  16  to  No.  18  U.  S.  standard  gaug 


(the  number  being  regulated  by  the  size  of  the  roo 


about 
one-eighth  of  an  inch  so  as(io  form  a  spring-post  or  pivo£^f/This 
is  easily  done  by  placing  the  wire  in  a  vise  and  steadily  cutting 
it  downward  through  the  center  with  a  saw-edged  strip  of  very 
thin  steel  (Fig.  410).  This  takes  only  a  few  minutes,  and  is 
preferable  to  partially  joining  two  pieces  of  half-round  wire. 

Pig.  409.  FlG-  414" 


lished  and  fitted  in  the  mouth,  the  inner 
be  having  been  closed  with  gutta-percha 

The  wire  is  then  tapped  together  at  the  slit,  burnished  smooth  and 
rounded  just  at  the  end  (B,  Fig.  409).  The  tube  for  this  pivot  is 
formed  by  once  encircling  the  pivot  with  a  piece  of  iridio-plati- 
num  plate,  No.  32  U.  S.  standard  gauge,  the  edge  of  which  is 
beveled  and  cut  to  meet  the  plate  even  and  close  (C).  .  The  pivot 
is  then  withdrawn,  and  the  seam  is  touched  along  its  length  with 
the  smallest  possible  quantity  of  borax.  The  proper  manner 
use  borax  in  fine  work  is  to  grind  it,  mixed  with  water,  on  a  si 
to  a  cream-like  consistence,  and  apply  on  the  point  of  a  camel's- 
hair  brush.  A  very  small  piece  of  pure  gold  is  placed  in  the 
seam,  and  the  tube  is  held  in  the  'flame  of  an  alcohol  lamp. 
When  a  sufficient  degree  of  heat  is  reached,  the  gold  will  flow- 
along  the  seam  and  form  a  joint  without  obstructing  the  inside 
passage  for  the  pivot.     The  pivot  is  then  inserted,  and  the  tube 


J*08 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


trimmed  (D)  and  gauged  in  a  gauge-plate.  With  a  drill  just 
the  size  of  the  tube  the  root-canal  is  enlarged  so  that  the  tube 
will  tit  in  tightly.  This  plan  prevents  weakening  of  the  root 
by  too  groat  enlargement  of  the  canal.  A  hole  the  size  of  the 
tube  is  made  through  the  cap,  and  cap  and  tube  are  then  ad- 
justed (Fig.  411),  and  the  pivot  being  withdrawn,  they  are  re- 
moved, invested,  and  soldered  (A,-Fig.  "31-2); //The  cuspid, 'which 


because  of  its  conical  formation  is  one  of  the  most  difficult  teeth 
in  the  mouth  to  clasp,  is  trimmed  sufficiently  to  partially  square 
its  approximal  sides,  and  the  palatal  portion  is  notched  slightly 


Fig.  411. 

I\\ 


Fig   413. 


Fig.  408. 


Fig.  412 

A 

and  th 

that  tS 

the  ca\ 

the    gol 

nearly  aJ| 

facilitate 

wood  or 

accurately 

in  the  rooie  clasp  to  rest  upon. 
in-   notch   can  Tie  safely  made,  as  the  enamel  is  very  dense  at 
the  point  indicated. 

A  -old  plate  is  swaged  to  till  the  space  between  the  central 
root  and  the  cuspid  as  shown  in  Fig.  412.  The  cap  and  pivot 
are  adjusted  on  the  central  root  and  the  plate  is  then  fitted  in 
the  mouth,  pressed  tightly  in  position  against  the  gum,  and 
retained  there  with  a  little  wax,  which  is  cemented  to  the  plate 
and  pressed  against  the  cuspid  and  side  of  the  cap.  An  im- 
pression of  the  parts  and  an  articulation  are  then  taken  in 
plaster.  The  cap,  pivot,  and  plate  being  removed  in  the  im- 
pression, they  will  he  presented  on  the  model  made  from  it  in 
exactly  the  same  position  ;i-  in  the  mouth.  A  second  or  outer 
cap  i-  then  ctmH&picted  for  tin'  root-cap,  the  band  being  made 
very   narrow  at  the  approximal   and   palatal   sides,  and  open  at 


REMOVABLE  PLATE  BRIDGES.  209 

the  labial  side,  as  the  porcelain  tooth  to  be  attached  will  serve  in 
its  stead  (B).  The  pin  is  then  soldered  fast  in  the  outer  cap,  and 
a  clasp  of  clasp  gold  (C),  No.  23  to  No.  24  U.  S.  standard  gauge, 
is  formed  to  extend  well  around  the  posterior  approximal  portion 
of  the  cuspid.  The  outer  cap  having  been  placed  in  position  on 
the  inner  one,  the  plate  extending  from  the  central  to  the 
cuspid  is  cemented  to  it  and  to  the  clasp  with  wax,  removed, 
invested,  and  the  parts  soldered  together.  Aided  by  the  plaster 
articulation,  teeth  are  ground  and  fitted  by  the  model,  backed, 
attached  to  the  plate  with  wax,  and  inserted  in  the  mouth. 
Platinum  foil  is  then  burnished  to  the  form  of  the  notch 
on  the  cuspid,  the  clasp  fitted  over  it  and  attached  with  wax, 
removed  with  the  plate,  and  soldered  to  it  simultaneously  with 
the  teeth. 

Fig.  414. 


When  the  piece  is  finished  and  fitted  in  the  mouth,  the  inner 
cap — the  end  of  the  tube  having  been  closed  with  gutta-percha 
— is  first  cemented  on  the  central  root.  A  very  small  quantity 
of  oxyphosphate  is  used,  and  while  it  is  yet  soft  the  plate  is 
adjusted  in  position,  and  allowed  to  remain  there  until  the 
cement  has  set.  The  split  pivot  is  sprung  open  a  little  and 
forced  to  place.  With  the  aid  of  the  clasp  around  the  cuspid  it 
will  be  found  to  perfectly  secure  the  plate.  Fig.  414  shows  the 
bridge  in  position.  If  the  plate  forming  the  bridge  is  tightly  ad- 
justed against  the  soft  tissues,  and  removed  in  that  position  in 
the  impression  taken  with  the  caps,  it  will  always  be  found  to 
tit  in  a  similar  manner  when  the  bridge  is  finished.  Should  the 
clasp  cause  decay  or  abrasion  of  the  cuspid,  the  tooth  can  be 
excavated  to  a  slight  depth  under  the  clasp,  and  filled  with  gold. 
This  is  best  done  by  making  a  few  retaining-pits,  filling  them 
with  a  hand-plugger,  and  then  inserting  the  main  body  of  the 

14 


210 


ARTIFICIAL  CROWS-  AM)  RRIDQE-WORK. 


gold  in  the  ordinary  manner,  the  Herbst  method  being  useful  in 
condensing  the  foil.  Such  a  tilling  inserted  at  any  time  will 
prevent  injury  from  a  clasp.  A  denture  of  this  style  can  be 
made  to  pass  intervening  teeth. 

In  the  artificial  replacement  of  the  lower  teeth  in  a  case  such 
a-  i>  illustrated  in  Fig.  415,  a  plate  bridge  possesses  many  advan- 
tages. In  the  construction  of  such  a  denture,  the  teeth  are  first 
properly  shaped.  Gold  crowns  (Fig.  416),  with  sides  as  nearly 
as  possible  parallel  the  one  with  the  other,  are  then  made  and 
fitted  to  the  bicuspid  and  molar.  This  operation  is  much  facili- 
tated by  shaping  the  external  surface  of  the  crown  with  metal. 
On  the  crowns,  at  the  buccal  sides,  a  narrow  shoulder  (A)  is  con- 
structed to  sustain  the  collars  and  bridge  in  position.     In  some 

Fig.  415. 


cases  this  shoulder  is  placed  on  the  approximal  side  to  better 
advantage.  The  crowns  are  then  adjusted  in  the  mouth,  a  small 
quantity  of  wax  being  applied  inside  of  the  crowns  when  neces- 
Bary  to  retain  them  in  correct  position.  A  piece  of  plate  is  next 
swaged  ami  fitted  between  the  crowns  and  attached  with  wax  as 
described  in  the  previous  case.  An  ir  session  and  articulation 
of  thai  part  of  the  mouth  are  then  taken  with  plaster  and  the 
crown-  and  plate  removed  in  it.  On  the  model  made;  from  this 
Impression  tie-  crowns  ami  plate  will  appear  in  position.  Collars 
reaching  from  the  cervical  t<>  the  occluding  edge  arc  fitted  to 
these  crown, a.  They  are  made  By  first  forming  ;i  collar  of  ample 
width  of  thin  platinum,  about  No.  -'5-  t<»  No.  34  V>.  8.  standarjl- 
gaiiL'e.  which  is  easily  adapted  \<>  the  form  of  the  crown,  and  on 
the  out-ide  of'  this,  fitting  a  slightly  narrower  Btfip  of  gold  clasp 


/,'  E  MOVABLE  PL  A  TK  BR  IDG  ES. 


211 


plate,  about  No.  30  U.  S.  standard  gauge.  The  gold  and  plati- 
num are  then  cemented  with  wax,  removed,  invested,  and  soldered 
together  with  gold  solder.  A  perfect-fitting  and  reliable  eollar 
is  thus  formed  (B,  Fig.  416). 

The  collars,  though  fitting  accurately,  should  move  easily  over 
the  crowns,  as  they  can  be  readily  tightened  when  the  case  is 
finished.  If  a  collar  is  troublesome  to  adjust  and.  remove,  cut 
the  side  opposite  to  the  one  attached  to  the  plate,  and  spring  it 
open  a  little.  After  fitting  the  teeth  it  can  be  again  "united 
when  they  are  being  soldered.  This  collar  and  shoulder  form  a 
supporbipreferable  to  a  partial  or  an  entire  double  cap,  being  less 
difficult  to  keep  clean.     A  collar  is  more  easily  constructed,  and 

Fig.  416. 


also  permits  the  position  of  the  bridge  to  be  altered,  by  the  removal 
of  a  little  of  the  shoulder  or  of  the  upper  edge  of  the  collar, 
and  is  a  secure  but  less  rigid  attachment  than  other  methods. 

The  collars  and  plate  are  next  cemented  with  wax,  removed, 
invested,  and  strongly  soldered  together  (B,  B,  Fig.  416).  The 
artificial  teeth  are  fitted  in  proper  position  on  the  plate  by  the 
aid  of  a  plaster  articu1,  ,-tion,  attached  with  wax,  and,  if  preferred, 
adjusted  in  the  mouth  without  the  crowns.  The  bridge  is  then 
invested  and  finished.  I  The  attachment  of  the  artificial  teeth  to 
fclie  plate  can  be  of  either  gold  or  rubber.  "Whichever  is  adopted, 
the  first  bicuspid  is  best  supported  by  being  soldered  to  the  collar. 
If  iridio-platinum  is  used  in  the  construction  instead  of  gold 
plate,  and  the  soldering  done  with  pure  gold,  porcelain  body 
can  be  used.  When  ready  to  be  inserted,  the  crowns  are  first 
adjusted  with  cement,  and  then  the  bridge,  which  is  left  in  posi- 


212 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


tion  until  the  cement  sets.  By  burnishing  the  collars  they  can 
be  made  to  clasp  the  crowns  as  firmly  as  desired.  Fig.  417  shows 
the  denture  in  position. 

Fig.  417. 


Figs.  418  and  419  represent  an  upper  removable  plate  bridge. 
In  its  construction  the  cuspid  roots  were  first  capped,  tubed,  and 
pivoted,  and  the  molars  crowned  with  shoulders  formed  on  the 

Fig.  418. 


Fig.  419. 


buccal  Bides.     The  plate  Intended  to  conned  the  abutments  was 
then  adjusted  in  position  as  1ms  been  described.     An  impression 

was  ii'\t  taken  and  a  model  and  articulation  made.      The  cuspids 


REMOVABLE  PLATE  BRIDGES. 


213 


were  then  double-capped  and  collars  formed  od  the  molar  crowns. 
The  douMe  caps,  pivots,  collars,  and  plate  were  next  soldered 
together.  The  artificial  teeth  were  attached  with  vulcanite,  the 
gum  section  being  formed  with  pink.  In  order  to  avoid  any 
warping,  which  might  readily  occur  in  the  construction  of  so 
large  a  denture  as  this,  the  plate  may  at  first  be  swaged  up,  as 
in  ordinary  artificial  dentures,  to  cover  the  whole  of  the  hard 
palate.  A  shallow  groove  can  be  made  around  the  palatal  sur- 
faces of  the  teeth,  and  after  the  final  soldering  the  plate  can  be 
cut  along  the  line  of  this  groove,  the  portion  covering  the  palate 
being  removed.    The  groove  will  insure  a  close  fit  for  the  palatal 

edge  of  the  plate. 

Fig.  420. 


In  the  case  represented  in  Fig.  420  the  natural  teeth  were 
very  short.  The  posterior  approximal  side  of  the  molar  was 
decayed  to  such  an  extent  that  the  pulp  was  nearly  exposed,  and 
considerable  irritation  of  the  investing  gum-tissue  had  been 
caused  by  the  clasp  of  a  plate  worn  by  the  patient  working 
upward  against  it.  The  patient  declined  to  have  a  plate  made 
which  would  extend  across  the  palate.  The  lateral  was  hardly 
strong  enough  to  support  a  permanent  bridge.  The  molar  was 
capped,  and  a  removable  appliance  constructed  with  a  band 
which  slipped  over  the  cap  and  rested  on  a  shoulder  on  the 
mesial  side  to  form  the  posterior  abutment.  The  lateral  was 
notched  and  clasped  for  the  anterior  support.  Figs.  421  and  422 
are  two  views  of  the  appliance  in  position. 


214  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  421. 


Fig.  422. 


Fig.  423. 


Fig.  424. 


REMOVABLE  PLATE  BRIDGES.  2,15 

Fig.  423  represents  a  case  in  which  a  central  incisor  jtrfeplaced 
«>n  an  extension  of  the  plate,  the  cuspid  being  partly  encircled 
by  a  clasp  with  a  shoulder  resting  on  the  palatal  section  of  the 
tooth.     Fig.  424  shows  the  denture  in  position. 

Fig.  425  represents  a  case  in  which  a  bridge-plate  was  inserted 
without  crowning  either  of  the  abutments.  The  clasp  of  a  plate 
which  had  been  worn  for  some  years  had  worked  upward  and 
abraded  the  distal  section  of  the  cuspid  to  such  an  extent  as 
to  expose  a  large  portion  of  the  root  and  superinduce  decay. 

Fia.  425. 

A        A 


The  cavity  was  filled  with  gold,  and  the  gingival  border,  by 
treatment,  brought  nearly  to  its  normal  position  on  the  tooth. 
A  plate  bridge,  such  as  is  represented  in  Figs.  426  and  427,  was 
then  constructed.  Clasps,  with  flanges  resting  on  little  shoulders 
formed  at  A,  A,  Fig.  425,  support  and  retain  it.  A  flange  such 
as  was  used  in  this  case  is  best  made  subsequent  to  the  con- 
struction of  the  plate  and  clasps,  by  burnishing  a  piece  of 
platinum  foil  in  the  mouth  to  the  form  of  the  shoulder  and  the 
side  of  the  tooth  upon  which  it  is  to  rest,  adjusting  the  clasp  over 
it,  and  cementing  with  wax,  then  removing,  investing,  and 
soldering.  Wherever  the  platinum  is  placed  the  solder  will  flow 
and  fill  all  the  space  between  it  and  the  clasp.  This  gives  the 
clasp  the  exact  form  of  the  tooth. 


216 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  428  shows  the  denture  finished  and  in  position.  If  the 
teeth  are  dense  in  structure,  an  attachment  of  metal  held  in 
proper  position  against  the  lower  portion  of  a  crown  will  be 
worn  a  long  while  before  it  causes  injury  to  the  parts.  Filling, 
or  crowning,  if  necessary,  can  subsequently  be  resorted  to. 

By  a  correct  application  of  the  methods  just  explained  and 
illustrated,  a  piece  of  removable  bridge-work  of  this  style  can 
ho  dovispd  for  mnny  r»n.sflfi. 


attachment  described  imm&m*dmmi*m 

can  also  be  used 
in  combination  with^liin  \\iy\t  wf  rirntnnrs. 

Fig.  429. 


Fig.  430. 


Pig.  \-'a  shows  the  easl  of  a  lower  jaw  in  which  only  the  lefil 

ond   molar,  Lefl   cuspid,  and  right    first    bicuspid   remained. 

The  molar  and  bicuspid  were  fitted  with  gold  cap  crowns,  and 


REMOVABLE  PLATE  BRIDQLS. 


217 


spring  socket  attachments  (Dr.  Parr's  form)  were  soldered  in 
proper  positions  on  the  crowns,  as  illustrated.  The  completed 
denture  in  position  supported  bv  the  attachments  is  seen  in  Fig. 
430.     The  under  side  is  shown  in  Fi«:.  431. 


Fig.  431. 


Fig.  432  represents  the  articulated  cast  of  a  case  in  which  a 
similar  form  of  attachment  and  a  clasp  were  used.  This  is 
illustrated  in  Fig.  433,  which  needs  no  description. 


Fig.  432. 


Fig.  433. 


Fig.  434  shows  the  den- 
ture in  place.  It  was  con- 
structed of  vulcanite,  and 
made  for  and  placed  in  the 
mouth  of  a  patient  exhibited 
at  a  clinic  of  the  Odonto- 
logical  Society  of  Pennsyl- 
vania, at  Philadelphia,  in  December,  1888.1 

1  Dental  Cosmos,  March,  1889. 


L'lS 


ARTIFICIAL  CROWN-  ASD  BRIDGE-WORK. 


DR.    WATERS'S    METHODS.1 

Dr.  T.  S.  Waters,  of  Baltimore,  explains  the  advantages  of  his 
removable  plate  bridge-work  as  follows :  "  In  the  system  I  pre- 
sent the  denture  is  retained  securely  and  steadily  in  the  mouth, 
yet  is  readily  removed  and  replaced  at  pleasure  by  the  wearer. 
The  pressure  and  strain  are  distributed  properly  over  all  the 
structures  and  tissues  available  for  the  purpose,  and  the  roots 
and  crowns  to  which  the  denture  is  attached  are  so  prepared 
that  there  is  no  place  for  the  lodgment  and  retention  of  food, 
and  when  the  denture  is  removed,  both  it  and  the  mouth  can  be 
thoroughly  cleansed.  Should  the  roots  or  other  tissues  be 
attacked  by  disease,  thus  requiring  treatment,  or  should  repairs 

Fig.  435. 


to  the  mechanism  become  necessary,  the  removable  bridge-work 
offers  facilities  for  those  purposes  not  to  be  found  in  permanent 
dentures." 

Dr.  Waters  thus  describes  the  formation,  combination,  and 
application  of  his  devices  to  cases  of  removable  plate  bridge- 
work  : 

•'  My  devices  are  three  in  number,  each  of  which  may  be  used 
alone,  or  two  of  them  or  all  three  may  he  combined  and  applied 
in  the  same  case,  as  the  position,  character,  and  relation  of  the 
teeth  and  roots  remaining  in  the  mouth  may  seem  to  indicate. 

'•The   fn-t    is  a  gold   crown    lifted   to  and  sliding  on   a  cap 


1  International  Dental  Journal,  April,  1889,  p.  197. 


REMOVABLE  PLATE  BRIDGES. 


219 


attached  permanently  to  the  root  or  natural  crown.  This  cap  is 
made  high  and  has  on  one  side  a  longitudinal  groove.  The  gold 
crown  has  soldered  on  the  inside  a  spring  catch,  which  works  in 
the  groove  on  the  cap,  and  holds  the  crown  firmly  in  its  place. 
The  character  of  the  device  is  >ee\\  in  application  to  the  case 
represented  in  Fig.  435.     Fig.  436  shows  the  denture  in  position. 

Fig.  436. 


Fig.  437  gives  the  lingual  aspect.  It  will  be  readily  seen  that 
under  proper  circumstances  two  or  more  roots  or  teeth  may  be 
fitted  with  this  device,  the  gold  crowns  being  soldered  to  and 
made  a  part  of  the  denture,  making  the  whole- a  piece  of  bridge- 
work  capable  of  being  removed,  cleaned,  and  replaced  at  will. 
The  spring  catch  regulates  the  firmness  of  retention.1 


Fig.  437. 


"  The  next  device  is  the  box  cap  and  split  post;  the  box  cap 
being  fitted  permanently  to  the  root,  and  the  split  post  being 
soldered  to  the  plate  bearing  the  teeth.  The  box  cap  is  the  usual 
cap,  with  a  box  or  tube  soldered  to  it  and  extending  into  the 
root,  the  cap  end  of  the  tube  being  open.  The  split  post  is  so 
secured  to  the  denture  as  to  slide  snugly  into  this  tube,  the  firm- 
ness of  retention  being  regulated  by  pressing  the  split  slightly 
open  when  necessary.     This  device,  like  the  first,  may,  under 

1  Dr.  Waters  ha?  patented  this  invention  and  donated  it  to  the  profession. 


220 


A  It  TIFICI.  1 L  CRO  WN-  A  XD  BRIDGE-  WORK. 


proper  circumstances,  l»e  used  by  itself  in  any  case,  as  shown  in 
application  in  Figs.  438,  439,  and  440,  in  which  the  whole  denture 
is  supported  by  1»<>x  caps  and  split  posts  adjusted  to  the  roots  of 
the  six  anterior  teeth. 


Fig.  438. 


S^~ 


Fig.  439. 


Fig.  440. 


"The  third  device  consists  in  soldering  to  the  side  of  the  gold 
crown  covering  the  natural  tooth  a  split  pin  or  post,  which  is 
inserted  into  the  open  tube  attached  to  the  denture. 

••  A-  before  remarked,  1 1 1 « - — « -  devices  may  !><■  used  singly  or  in 
combination  in  any  one  case.     En  one  of  the  dentures  illustrated 


REMOVABLE  PLATE  BRIDGES. 


221 


thf  box  cap  and  split  post  alone  are  used;  in  another,  the  cup. 
gold  crown,  and  sprirjg  catch  are  used;  in  the  case  illustrated  in 
Figs.  441,442,  and  443  the  three  are  applied,  in  which  the  entire 
denture  is  attached  to  and  retained  by  two  cuspids,  a  bicuspid, 

Fig.  441. 


and  a  molar.  In  all  this,  great  care  must  of  course  be  taken  in 
the  preparation  of  the  roots  and  natural  crowns,  to  protect  them 
against  the  action  of  destructive  agents." 


CHAPTER  X. 

THE  LOW  BRIDGE. 

Dr.  J.  E.  Low,  of  Chicago,  is  the  reputed  inventor  of  bridge- 
work  formed  with  self-cleansing  spaces  and  supported  by  means 
of  cemented  collars  or  collar  crowns.1 

The  following  is  Dr.  Lowr's  method  of  using  his  step-plug 
crown  (see  page  126)  in  conjunction  with  all-gold  cap  crowns  in 
bridge-work.  Fig.  444  shows  a  case  with  the  prepared  molar 
crowns  and  cuspid  roots.  The  bridge  constructed  according  to 
this  method  is  seen  in  Fig.  445,  and  adjusted  in  position  in  Fig. 
446.  Figs.  447,  448,  and  449  illustrate  a  case  of  four  incisors 
Hipported  by  two  step-plug  crowns  on  the  cuspids. 

Dr.  Low  gives  the  following  instructions  relating  to  the  con- 
struction of  shell  crowns  or  anchorages  on  cuspids,  to  support  a 
bridge  of  the  four  incisors  in  a  case  such  as  is  shown  in  Fig.  450 : 
"  I  first  measure  the  tooth  with  strips  of  tin,  and  make  the  gold 

1  The  construction  of  bridge-work  supported  by  collars  or  any  form  of  collar 
crowns  cemented  on  teeth  or  root?,  according  to  a  recent  judicial  decision,  is  not 
at  present  free  to  public  use.  The  two  claims  which  reserve  the  use  of  these 
methods  to  the  inventor  as  specified  in  the  letters  patent  granted,  are  as  follows: 

"What  I  now  claim  as  new  is:  1.  The  herein-described  method  of  inserting 
and  supporting  artificial  teeth,  which  consists  in  attaching  said  artificial  teeth  to 
continuous  bands  fitted  and  cemented  to  the  adjoining  permanent  teeth,  whereby 
laid  artificial  teeth  are  supported  by  said  permanent  teeth  without  dependence 
upon  the  gum  beneath. 

"  2.  An  artificial  tooth  cut  away  at  the  back,  so  as  not  to  present  any  contact 
with  the  gum  except  along  its  front  lower  edge,  and  supported  by  rigid  attach- 
ment to  one  or  more  adjoining  permanent  teeth,  substantially  as  and  for  the 
purpose  >et  forth." 

A  <!'-nture  between  two  or  more  teeth  or  roots,  supported  by  such  means  as  bars 
extending  from  it  anchored  into  teeth  or  caps  or  crowns  which  do  not  encircle  the 
t'  >-tli  or  roots,  with  th^  artificial  teeth  rei-ting  on  or  pressing  into  the  gums  and 
not  formed  with  what  are  termed  and  described  as  self-cleansing  spaces,  and 
removable  bridge-w  nrk,  are  not,  in  the  opinion  of  experts,  included  in  the  mean- 
ing or  ipeciflcations  of  this  patent.— G.  E. 
222 


THE  LOW  BRIDGE. 


223 


bands  and  cut  out  the  outside  lower  portion  of  the  band  before 
beginning  to  tit.  In  tittinsr,  as  the  band  is  beins:  driven  down,  cut 
away  any  of  the  band  that  touches  the  gum  before  all  touches; 
never  drive  the  band  under  the  gum,  as  inflammation  will  prob- 

Fig.  444. 


ably  follow.  I  mention  this,  as  I  have  seen  many  attempts  to  get 
rid  of  the  bands  by  driving  up  under  the  gums  and  cutting  them 
out  on  the  front,  until  they  are  too  narrow  for  strength.     The 


224 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


bands  should  be  heavy  and  strong,  and  the  patient  should  under- 
stand that  if  he  expects  to  get  rid  of  the  annoyance  of  the  plate 
he  must  sacrifice  his  dislike  to  showing  gold.  After  driving  the 
hands  up  close  to  the  margin  of  the  gums,  as  the  cuspid  teeth 
aii-  very  tapering,  the  bands  will  have  to  be  taken  in  at  the 

Fig.  447. 


bottom.  To  do  this  I  slit  the  band  about  a  third  of  its  length 
up,  then  place  it  on  the  tooth  again,  lap  it  over  to  bring  it  to  a 
close  fit.  and  then  take  it  off  and  solder.  Continue  taking  it  in 
wherever  it  does  not  perfectly  fit  the  tooth,  and  after  a  good  fit 
Fio.  448.  Fig.  449. 


i-  obtained  proceed  with  the  construction  of  the  bridge  by  taking 
an  impression  and  articulation. 

•■In  adjusting  the  bridgewhen  finished,  first  try  it  on  to  sec 
thai  it  fn-  and  that  tin'  articulation  is  all  right.  Fig.  451  shows 
tli,  !v  for  adjustment.    Nex1  dry  the  teeth  upon  which  tin' 


THE  LOW  B JUDGE. 


225 


bands  are  going,  and  then  mix  your  cement.  This  should  be 
mixed  to  about  the  consistence  of  thick  cream.  It  must  be 
neither  too  thick  nor  too  thin,  or  the  adhesion  will  not  be  strong 
enough  to  hold.     Cover  your  teeth  with  cement,  and  then  the 


Fig.  450. 


inside  of  the  bands.  Place  these  on  the  teeth  and  carefully 
mallet  up  into  position.  For  this  purpose  I  use  a  steel  instru- 
ment with  a  crease  or  groove  in  the  end.  The  teeth  must  be 
kept  dry  after  the  case  is  in  position  until  the  cement  is  well  set. 


Fig.  451. 


Fig.  452. 


After  this  is  done  bevel  the  edges  of  the  bands  and  burnish  close 
to  the  teeth,  and  if  properly  done  they  will  resemble  gold  fill- 
ings. In  Fig.  452  we  have  the  case  completed.  I  always 
impress  upon  my  patients  the  necessity  of  having  the  case  reset 

15 


226 


ARTIFICIAL  CROWX-  AND  BRIDGE-WORK. 


immediately  should  it  become  loose,  and  advise  them  to  have 
their  cases  examined  jit  least  once  a  year." 

Dr.  Low  has  invented  for  use  in  crown-,  or  bridge-work  a 
ready-made  metallic  socket  or  shell,  into  which  fits  a  correspond- 
ing porcelain  front,  which  can  be  replaced  in  case  of  fracture. 


Fig.  453. 


Fig.  454. 


Fig.  455. 


Fig.  456. 


Fig.  457. 


/ 


Fig.  45£  shows  a  socket  shell.     Figs.  454  and  455  represent  a 

socket  with  the  porcelain  in  position.     Fig.  456  represents  the 

socket  as  made  for  the  incisors  and  cuspids,  and  Fig.  457  the 

jorcelain  in  position. 


CHATTER    XL 


DR.    KNAPP'S   METHODS. 

Dr.  J.  Rollo  Knapp,  of  New  Orleans,  has  introduced  some 
novel  methods  in  crown-  and  bridge-work,  for  effecting  artistic 
results  and  continuity  of  structure. 

In  crown-work,  Dr.  Knapp  invests  for  soldering  so  that  the 
parts  to  be  united  and  filled  form  a  miniature  mold.  Into  this 
mold,  at  a  high  heat,  with  a  pointed  flame  from  his  blow-pipe, 
he  flows  solder,  which  fills  the  interstices,  joins  the  parts,  and 
assumes  the  form  of  the  mold.  The  following  is  a  brief  descrip- 
tion of  his  methods: 


Fig.  458. 


Fig.  459. 


Fig.  460. 


In  constructing  a  gold  collar  crown  with  porcelain  front,  for 
an  incisor  or  cuspid,  22-carat  The  S.  S.  White  Mfg.  Co.'s  collar 
gold,  No.  28  standard  gauge,  is  used  for  the  collar,  which  is  formed 
by  adapting  the  gold  to  the  root  by  the  aid  of  pliers.  The  cap  to 
the  band  is  then  made  of  pure  gold,  No.  34  gauge,  and  a  gold 
pin  soldered  in  position  for  the  root-canal.  A  plate  tooth  is  then 
ground  in  proper  position,  backed  with  pure  gold,  and  fastened 
to  the  cap  with  wax.  On  being  removed  from  the  mouth  after 
proper  adjustment,  the  side  and  incisive  portions  of  the  wax, 
including  the  edges  of  the  backing  and  contiguous  portions  of 
the  cap,  are  completely  enveloped  with  pieces  of  pure  gold  No. 
34  gauge  (Figs.  458  and  459).  The  crown  is  then  invested  so 
that  when  the  wax  is  removed  the  backing  on  the  tooth  with  the 

227 


228 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


gold  on  the  sides  shall  form  a  small  mold  or  pocket  (Figs.  460 
and  461).  When  the  investment  is  heated,  the  flame  of  his 
blow-pipe  is  played  over  its  surface  until  the  mass  is  aglow, 
when  the  point  of  the  flame  is  thrown  into  the  mold  by  rapid 
thrusts  until  the  solder  melts  like  wax  and  fills  every  part  of  the 
mold  with  liquid  gold.  This  gives  an  excess  of  gold  which 
affords  ample  facilities  for  contouring  in  the  process  of  finishing 
(Figs.  462  and  463). 


Fig.  461. 


Fig.  462. 


Fig.  463. 


Fig.  464. 


In  constructing  a  bicuspid  crown  with  porcelain  face,  the 
natural  tooth  is  ground  down  to  the  gingival  edge  and  capped 
similar  to  a  cuspid.  A  bicuspid  porcelain  front  is  then  ground 
and  fitted  in  position  (Fig.  464),  and  the  remaining  portion  of 
the  crown  is  shaped  in  wax  to  the  form  required.  A  die  of  the 
grinding-surface  is  then  made  in  metal,  a  cap  stamped  in  pure 


Fig.  465.  Fig.  466. 


Fig.  467. 


Fig.  468.  Fig.  469. 


gold,  Xo.  34  U.  S.  standard  gauge  (Fig.  465),  and  the  cusps 
filled  with  20-carat  gold  solder.  This  cap  is  next  trimmed  (Fig. 
466)  90  as  to  fit  when  placed  in  proper  position  against  the  end 
of  the  porcelain  cusp,  tor  which  purpose  sufficient  wax  must  be 
removed.  The  approximal  surfaces  are  enveloped  and  the 
palatal  portion  of  the  collar  protected  with  pieces  of  pure  gold, 


DR.  K  SAP  PS  METHODS. 


229 


Xo.  34  standard  gauge,  which  are  slit  to  facilitate  their  adjust- 
ment (Fig.  467).  This  leaves  the  palatal  portion  open  when  the 
crown  is  invested  and  the  wax  removed,  which  last  should  be 
done  with  hot  water.  Fig.  468  shows  the  invested  crown  ready 
for  soldering,  in  which  operation  the  parts  are  filled  in  and 
joined  with  20-carat  gold  solder.  The  result  when  finished  is  a 
solid  gold  crown  with  a  porcelain  front  (Fig.  469). 

All-gold  bicuspid  and  molar  crowns  are  formed  by  Dr.  Knapp 
in  a  similar  manner,  but  as  porcelain  fronts  are  not  used  in 
these  cases,  the  thin  gold  plate  is  placed  entirely  around  the 
labial  aspect  of  the  wax  model.  In  crown-work,  after  the  cap 
has  been  made,  an  impression  is  generally  taken  and  a  plaster 


Fro   470. 


Fig.  471. 


model  and  articulation  made  to  facilitate  the  subsequent  con- 
struction. 

Dr.  Knapp'a  method  of  constructing  bridge-work  is  similar  to 
that  in  general  use  except  in  the  investing  and  the  soldering  of 
the  parts  together,  the  latter  being  done  with  the  blow-pipe  in  a 
manner  similar  to  that  above  described. 

Figs.  470  and  471  illustrate  specimens. 

Dr.  Knapp's  compound  blow-pipe  (Fig.  472)  consists  of  a 
miniature  blow-pipe  in  which  the  ordinary  illuminating  gas 
(carburetted  hydrogen  or  coal-gas)  flame  is  combined  with  a 
current  of  nitrous  oxide  from  a  cylinder  of  the  condensed  gas. 
The  combination  of  these  gases  in  combustion  forms  essentially 


230 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


a  carbo-oxyhydrogen  iiame.1  By  means  of  a  yoke  and  set- 
screw,  the  valve  of  the  cylinder  is  connected  with  the  tubes  and 
valves  of  the  blow-pipe,  so  that  the  proportions  of  the  mixture 

Fig.  472. 


1  The  ordinary  compound  oxy hydrogen  blow-pipe  flume  is  produced  by 
2  volume*  of  hydrogen  ;   1  volume  of  oxygen. 

Carburetted  hydrogen  consists  of 

2  volumes  of  hydrogen  ;   1  volume  of  carbon. 

And  nitrous  oxide  of 

-  volumes  <>f  hydrogen  ;  1  volume  of  oxygen. 

Consequently  Knapp'a  blow-pipe  flame  is  produced  by  a  mechanical  mixture  of 
2  volumes  of  hydrogen  ;   1  volume  of  oxygen  ;   1  volume  of  carbon. 


DR.  KXAPP'S  METHODS.  231 

of  nitrous  oxide  and  the  illuminating  gases  are  under  perfect 
control.  The  flame-jet  can  be  diminished  to  half  an  inch  in 
length,  and  at  that  size  will  melt  a  small  piece  of  gold  plate. 

This  blow-pipe  is  useful  for  many  purposes  in  the  laboratory  of 
the  present  time,  especially  in  forming  solid  gold  backings  to 
dummies  for  bridge-work,  strengthening  seamless  gold  crowns, 
and  forming  solid  gold  crowns. 

Dr.  Knapp  has  exhibited  to  the  profession  some  very  fine 
specimens  of  crown-  and  bridge-work,  and  presented  much  that 
is  novel  and  interesting,  as  well  as  encouraging  to  the  artistic 
element  of  prosthetic  dentistry.  The  real  value  of  processes  or 
methods,  however,  depends  on  their  practicability.  Therefore, 
in  contemplating  that  which  is  novel  and  beautiful  in  connection 
with  dental  art,  we  must  be  governed  by  this  fact  in  estimating 
its  value.  Judged  from  this  stand-point,  Dr.  Knapp's  special 
methods,  while  admitting  of  the  highest  artistic  results,  embrace 
some  processes  which,  on  account  of  their  intricacy,  are  not 
likely  to  be  generally  adopted  in  practice. 


CHAPTER    XII. 

DR.    MELOTTE'S    METHOD. 

Dr.  G.  W,  Melotte,  of  Ithaca,  N.  Y.,  describes  the  construc- 
tion of  a  bridge  supported  by  a  gold  crown,  and  a  shell  or  par- 
tial gold  crown,  and  the  use  of  his  invention,  "  moldine,"  in  con- 
nection with  fusible  metal  in  crown-  and  bridge-work,  as  follows  : l 

"  Fig.  473  illustrates  a  case  for  the  supply  of  a  lateral  and  a 

bicuspid.     In  this  instance  the  cuspid  could  be  cut  off,  and  the 

root  collared  and  capped  in  combination  with  a  pin  entering  the 

enlarged  root-canal;  but  as  there  may  be  grounds  for  objection 

^       ,„„  to  cutting  off  sound  teeth,  I  ob- 

Fig.  473.  .  &  .  '. 

viate  the  necessity  by  cutting  a 

shoulder  on  the  lingual  portion 

of   the    cuspid,    and     suitably 

shaping  its  sides  to  permit  a  close 

fitting  of  the  collar  just  under 

the  free  margin  of  the  gum.     A  narrow  strip  of  pure  pattern 

tin,  bent  tight  around  the  tooth-neck,  and  cut  through  with  a 

knife  at  the  lap  on  the  labial  surface,  will  serve  as  a  measure  for 

the  length  of  a  strip  of  22-carat  gold  plate,  No.  29  thick,  and  as 

wide  as  the  length  of  the  distal  side  of  the  cuspid.     The  ends  of 

the  gold  are  then  squared,  and  with  round-nosed  pliers  brought 

nly  together,  to  be  held  in   flush   contact  by  the  soldering- 

clamp  ae  shown  in  Fig.  474.     The  soldered  collar,  with  its  joint 

inward,  is  then  adjusted  OD   the  tooth  as  accurately  as  pos- 

sible,  giving  -light  blow-  with  a  mallet    until   the  collar  touches 

the  gum,  when   it   -hould  be  marked  to  indicate  the  necessary 

trimming  to  conform  it  to  the  gum  contour.     After  it  has  been 

thus  trimmed,  the  edges  beveled,  the  labial  part  swelled  with 

contouring  pliers,  and  the  lingual  part  cut  down  to  about  one- 

1  Dental  C-ismoa,  vol.  xxviii,  No.  12,  page  745. 
232 


DR.  MELOTTE'S  METHOD. 


533 


tenth  of  an  inch  in  width,  the  collar  is  again  driven  on,  and  will 
appear  as  seen  in  Fig.  473.  A  stump  corundum-wheel  is  then 
used  to  grind  a  shoulder  on  the  lingual  surface  of  the  tooth, 
grinding  also  the  edges  of  the  collar  flush  with  the  shoulder. 
The  collar  is  again  removed,  and  a  piece  of  thin  platinum  plate, 
about  No.  32, -sufficient  to  cover  the  lingual  surface  of  the  tooth, 
is  caught  on  this  lingual  edge  of  the  collar  by  the  least  bit  of 
solder,  and  all  put  in  place  on  the  cuspid  (Fig.  475).  The 
platinum  should  now  be  burnished  on  to  the  shoulder,  and  over 
the  tooth  and  collar  to  the  extent  shown  by  the  lines  in  Fig.  475. 

Fig.  474. 


After  trimming  to  those  lines,  and  careful  replacement  and 
burnishing  on  the  tooth,  the  collar  and  half-cap  are  removed, 
filled  with  wet  plaster  and  marble-dust,  and  the  platinum  soldered 
to  the  gold.  It  is  then  placed  on  the  tooth,  burnished  into  all  the 
inequalities  of  the  tooth,  very  carefully  removed,  invested,  and 
enough  solder  flowed  over  the  FlG.  475  FlG.  476.  FlG  477- 
platinum  to  cover  and  give  it 
strength.  Fig.  476  shows  it 
complete  on  the  cuspid. 

"  I  have  feared  that  a  detailed 
statement  would  imply  a  long       '<      1        •  "=" *** 

and  tedious  process,  but  I  have 

often  made  such  collars  in  less  than  an  hour,  and  in  any  case 
time  must  be  made  subservient  to  exactness  of  fit  and  adaptation 
to  the  end  in  view. 

"  In  the  preparation  for  fitting  a  collar  on  the  first  molar  (Fig. 
473),  I  should  have  wedged  or  otherwise  separated  it  from  the 
second  molar,  so  that  a  piece  of  sheet  brass  might  be  put  in 
place,  as  shown  by  Fig.  477,  and  an  impression  taken  in  plaster, 


234  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

which  if  allowed  to  get  hard  would  bring  away  the  metal.  If 
not,  it  could  bo  replaced  in  the  plaster.  Melted  fusible  metal y 
when  near  the  cooling-point,  is  then  poured  into  the  impression, 
and  when  cold  will  allow  the  safe  removal  of  both  the  plaster 
and  the  metal  strip.  On  this  metal  model  a  collar  can  be  formed 
that  will  accurately  fit  the  molar,  as  seen  in  Fig.  473.  If  the 
molar  has  no  antagonist,  a  cap  may  at  once  be  struck  up  on  the 
model;  but  if  there  be  an  antagonist  the  cusps  of  the  natural 
molar  should  be  removed  bv  grinding  at  points  where  the 
occluding  tooth  will  admit  of  sufficient  thickness  of  the  gold 
cap.  An  exact  copy  of  the  ground  cusps  can  then  be  made  in 
less  than  five  minutes,  by  the  use  of  moldine  with  its  acces- 
sories, and  the  process  is  as  follows  :  Make  the  tooth  perfectly 
dry.  Put  the  collar  on  it.  Nearly  fill  the  cup  with  moldine, 
and  coat  it  with  soapstone  powder.  Press  the  compound  on  the 
tooth  and  collar  firmly  to  about  one-fourth  the  depth  of  the 
tooth.  Carefully  remove  the  cup;  trim  off  any  overhanging 
material,  and  place  the  rubber  ring  over  the  cup  to  about  one- 
half  the  depth  of  the  ring.  Melt  the  fusible  metal  and  pour  it 
as  cool  as  it  will  run  from  the  iron  ladle.  As  soon  as  the  metal 
is  hard,  remove  it  with  the  ring,  taking  care  not  to  impair  the 
impression,  which  can  be  used  again  if  the  die  is  found  imperfect 
or  gets  injured  in  use.  Place  the  die  and  ring  in  cold  water,  to 
remain  until  quite  cooled.  While  the  die  is  wet  and  held  over  a 
basin  of  water,  pour  into  the  ring  fusible  metal  which  has  been 
stirred  until  it  begins  to  granulate,  and  quickly  immerse  all  in 
the  water.  The  die  and  counter-die  should  separate  readily  by 
tapping  them  with  a  hammer,  but  if  they  stick  others  can  be 
quickly  made  from  the  same  impression  by  the  same  method, 
using  more  care.  With  this  die  and  its  counter-die,  a  piece  of 
No.  2!t  "v  :;0  gold  plate  is  swaged  to  fit  perfectly  the  cusps  and 
collar,  which,  when  removed,  can  be  held  to  its  place  on  the  cap 
by  the  soldering-clamp,  using  spring  pressure  enough  merely  to 
hold  them  together  for  careful  soldering  with  the  pointed  flame 
-o  as  not  to  unsolder  the  collar.  The  seamless  collars  are  excel- 
lent when  care  is  used  in  selecting  the  proper  size,  as  directed 
on  the  diagram  (see  page  246). 

"  The  caps  being  in  place  on  the  cuspid  and  molar,  an  impres- 


DR.   MELOTTE'S  METHOD.  235 

sion  is  taken  with  plaster ;  the  caps  accurately  set  in  the  impres- 
sion, and  hard  wax  melted  with  a  hot  spatula  around  the  edges 
of  the  caps.  The  impression  is  then  thoroughly  coated  with 
sandarac  varnish,  after  which  it  is  dipped  for  a  moment  in  water, 
and  filled  with  a  wet  mixture  of  one  part  marble-dust  with  two 
parts  of  plaster ;  using  great  care  to  perfectly  fill  the  caps  and 
molds  of  the  teeth.  Wait  until  this  mixture  has  become  quite 
hard ;  remove  the  cup,  and  with  a  suitable  knife  chip  oif  the 
plaster  without  marring  the  cast;  secure  a  good  articulating 

Fig.  478. 


impression  and  transfer  it  to  the  cast  to  obtain  an  exact  repro- 
duction of  the  relative  occlusions  of  all  the  teeth  involved. 
With  such  an  articulation  in  hand,  and  with  the  means  already 
described  for  swaging  gold  or  platinum  plate  to  fit  the  cusps  and 
articulating  surfaces  of  either  the  natural  or  artificial  teeth,  it 
should  be  within  the  capacity  of  any  competent  dentist  to  com- 
plete a  suitable  bridge ;  although  there  are  practical  points  that 
can  only  be  imparted  by  clinical  instruction  and  actual  demon- 
stration in  the  mouth.  Such  a  bridge  is  shown  in  position  by 
Fig.  478." 


CHAPTER    XIII. 

PARTIAL   CAP   AND   PIN-BRIDGE   METHODS. 

Dr.  TV.  F.  Litch's  processes  in  this  style  of  work  have  for 
special  cases  many  decided  advantages,  and  are  thus  described 
by  him : 1 

"  Fig.  479  represents  a  typical  case,  in  which  a  lateral  incisor 
(crown  and  root)  has  been  lost,  the  cuspid  and  front  incisor,  fully 
vitalized,  and  without  approximal  carious  cavities,  remaining  in 
position. 

"  To  Make  a  Pin  and  Plate  Bridge. — 1.  Take  in  plaster  an 
accurate  impression  of  the  cuspid  and  incisor  and  the  interspace. 
From  this  obtain  a  plaster  model  of  the  parts. 

Fig.  479. 


"  2.  Make  from  pure  gold,  rolled  to  the  thinness  of  No.  26, 
standard  gauge,  base-plates,  to  be  carefully  adjusted  to  the  palato- 
approximal  surfaces  of  the  cuspid  and  incisor.  These  can  be 
made  l»y  swaging  on  dies  and  counter-dies  obtained  from  the 
model,  bu1  more  conveniently  by  bending  the  gold  into  shape 
upon  flic  plaster  model  and  pressing  and  burnishing  it  into 
perfect  adaptation  upon  the  natural  teeth. 

"  3.  Select  a  plain  plate  porcelain  tooth  of  suitable  length, 
Bbape,  ami  shade,  and  wide  enough  to  fit  easily  into  the  inter- 
space.    Lei  the  neck  of  the  tooth  rest  lightly  upon  the  gum. 


1  Dental  Cosmos,  vol.  xxviii,  No.  8. 


PARTIAL  CAP  AND  PIN-BRIDGE  METHODS.  237 

"  4.  With  pure  gold  or  platinum  make  a  backing  for  the  por- 
celain tooth. 

"  5.  Place  the  tooth  thus  prepared  and  the  base-plates  already 
made  upon  the  cast  and  accurately  adjust  the  approximal  edges 
of  the  base-plates  to  the  backing  of  the  porcelain  tooth  in  situ 
upon  the  cast. 

"  6.  "When  this  adjustment  is  made,  cement  together  the  base- 
plates and  backing  with  a  brittle,  resinous  cement  (resin,  two 
parts;  wax,  one  part;  or  sealing-wax  will  answer),  and  before 
the  cement  has  fully  hardened  remove  from  the  cast  to  position 
in  the  mouth,  perfecting  the  final  adjustment  there.  By  this 
method  much  greater  accuracy  of  adaptation  is  obtained,  as  the 
lines  of  length,  width,  and  contour  are  too  fine  to  be  repro- 
duced with  absolute  fidelity  in  a  plaster  model.  In  this  part  of 
the  process  too  much  care  cannot  be  taken  to  have  each  piece  of 
the  appliance  fitted  with  absolute  accuracy  to  the  surface  for 
which  it  is  designed.  When  this  has  been  accomplished,  throw 
upon  the  yet  more  or  less  plastic  cement  a  stream  of  ice-cold 
water  from  an  office  syringe ;  this  renders  the  cement  perfectly 
brittle  and  incapable  of  bending.  This  done,  immediately 
remove  from  the  mouth  and  invest  in  a  mixture  of  equal  parts 
of  marble-dust  and  plaster  of  Paris. 

"  7.  After  the  investment  has  firmly  set,  solder  the  base- 
plates to  the  backing,  and  the  backing  to  the  platinum  pins  of 
the  porcelain  tooth,  using  as  a  solder  20-carat  gold.  Thus 
joined,  the  appliance  will  present  the  appearance  shown  in  Fig. 
483, — A  representing  the  base-plate  for  the  cuspid  ;  B,  the  base- 
plate for  the  incisor;  C,  the  porcelain  tooth  with  its  platinum 
backing ;  D,  the  points  of  union  between  the  base-plates  and 
backing.  At  these  points  the  greatest  strength  is  required,  and 
it  is  important  that  here  a  large  amount  of  the  solder  should  be 
placed.  The  porcelain  tooth  being  usually  thinner  than  the 
natural  teeth,  there  is  nearly  always  an  angle  or  depression  at 
the  points  indicated,  in  which  the  thickness  of  the  gold  can  be 
considerably  increased  without  interfering  with  occlusion. 

"  8.  For  the  purpose  of  attaching  the  denture  as  thus  far  con- 
structed, drill  a  small  cylindrical  opening  through  the  palatal 
surface  of  the  enamel  of  the*  cuspid  and  incisor  respectively. 


238  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

These  openings  should  usually  be  placed  about  as  indicated  in 
Fio-.  482,  at  C,  D/  Sometimes,  owing  to  a  close  occlusion  or  to 
the  contour  of  the  tooth,  it  is  desirable  that  they  should  be  located 
a  trifle  nearer  the  neck  of  the  tooth.  Each  opening  should  be 
well  undercut,  but  must  not  encroach  upon  the  dentine  far 
enough  to  endanger  the  pulp.  In  size  the  openings  need  not 
be  larger  than  will  admit  a  platinum  pin-head,  in  diameter  cor- 
responding  to  Xo.  13,  standard  gauge,  with  a  shank  of  No.  18, 
standard  gauge.  Into  each  of  these  openings  must  be  fitted  a 
platinum  pin  of  the  size  indicated.  The  head  of  each  pin  must 
be  made  thin  and  perfectly  flat  both  upon  its  upper  and  under 
surfaces.  (J 

"  9.  In  each  of  the  base-plates  make  an  opening  corresponding 
in  position  to  those  in  the  natural  teeth.  Pass  through  these 
openings  and  cement  in  them  the  free  ends  of  the  platinum  pins. 

Fia.  480.  Fig.  481. 


E 

While  the  cement  is  yet  plastic,  place  the  denture  in  position  in 
the  mouth,  carefully  pressing  the  pin-heads  into  the  openings 
made  for  them,  and  burnishing  the  base-plates  into  perfect 
contact  with  the  palatal  surfaces  of  the  teeth;  chill  the  cement, 
remove  and  invest  as  before,  and  with  20-carat  gold  solder  the 
pins  to  the  base-plates,  flowing  upon  them  and  the  backing  as 
much  of  the  solder  as  may  be  necessary  to  give  them  the  desired 
thickness  and  rigidity;  the  amount  admissible  largely  depend- 
ing upon  the  nature  of  the  occlusion;  a  central  thickness  of 
about  N<>.  21,  standard  gauge,  being  all  that  is  really  requisite 
for  strength,  while  the  edges  can  be  made  much  thinner. 

"  Fig.  180  represents  the  appliance  without  the  pin.  A  is  the 
porcelain  tooth  and  backing;  E,  the  base-plates ;  C  and  F,  the 
openings  for  the  pins. 

"Fig.  481  represents  the  appliance  completed  with  the  Dins  in 
position.  .  ^J^  ffL 


PARTIAL  CAP  AND  PIN-BRIDQE  METHODS. 


239 


"  Fig.  482  represents  the  natural  teeth  and  interspace  B,  with 
openings  for  retaining-pins,  C,  D. 

"  Fig.  483,  already  described,  represents  the  appearance  pre- 
sented when  the  bridge  is  cemented  in  position. 

"  To  Attach  thi  Bridge. — To  attach  the  bridge  the  best  attaina- 
ble oxyphosphate  cement  should  be  used.  It  is  desirable  that  it 
should  set  slowly.     Thoroughly  dry  the  teeth  and  denture;  mix 

Fro.  482. 


the  cement  to  as  thick  a  consistence  as  is  compatible  with  per- 
fect plasticity.  A  thick,  viscid,  semi-fluid  mass  is  what  is 
required.  With  suitable  instruments,  swiftly  but  carefully  place 
the  cement  around  the  head  and  shank  of  each  platinum  pin, 
and  also  in  the  openings  in  the  natural  teeth.  This  care  is 
necessary  in  order  to  exclude  all  air-bubbles  and  thoroughly 
engage   the   pin-heads   in   the   cement.      They   furnish    ample 


retaining  surface,  but  none  to  spare.  In  packing  the  cement 
around  the  pins  the  under  surface  of  the  base-plates  should  at 
the  same  time  be  covered. 

"  The  above  details  being  perfected,  the  denture  is  at  once 
carried  to  position,  and  with  broad-pointed,  serrated  instruments 
pressed  firmly  into  place,  the  excess  of  cement,  if  of  the  proper 
consistence,  freely  oozing  at  all  margins." 


240  ARTIFICIAL   <RU\VN-  AND  BRIDGE-WORK. 

"Application  to  Pulpless  Teeth. — In  the  above  description  the 
vitality  of  the  pulps  of  the  cuspid  and  incisor  has  been  assumed  ; 
but,  as  can  readily  be  understood,  the  pin  and  plate  bridge  can 
be  even  more  easily  and  securely  placed  when  one  or  both 
pulps  are  devitalized,  for  the  reason  that,  the  pulp-chamber  being 
empty,  the  pin-holes  in  that  tooth  can  be  made  as  much  larger 
and  deeper  as  may  be  deemed  desirable,  the  size  of  the  pin  being, 
of  course,  correspondingly  increased.  In  a  devitalized  tooth, 
too,  the  base-plates  can  be  sunk  into  the  palatal  surface  when 
they  interfere  with  occlusions,  as  sometimes  happens  when  the 
antagonism  of  the  lower  teeth  is  very  close  and  the  overlap  is 
considerable. 

"  Ordinarily,  however,  such  interference  is  inconsiderable,  and 
the  difficulty  can  always  be  overcome  either  in  devitalized  teeth 
by  the  expedient  just  suggested,  or  by  carrying  the  base-plates 
as  far  away  from  the  cutting-edge  as  practicable,  at  the  same 
time  making  them  at  the  point  of  contact  as  thin  as  is  consistent 
with  strength ;  finally,  if  necessary,  removing  a  slight  portion 
of  the  cutting-edge  of  the  occluding  lower  tooth.     .     .     . 

"  As  a  rule  the  writer  has  confined  the  use  of  this  form  of 
bridge  to  cases  in  which  only  a  single  incisor  is  missing,  but  he 
has  successfully  attached  a  front  and  lateral  incisor  to  a  cuspid 
and  the  remaining  front  incisor.  Where  an  unusual  strain 
is  to  be  expected  the  retaining-pins  and  pin-holes  should  when 
practicable  be  made  correspondingly  large,  or  two  smaller  pins 
may  be  anchored  in  one  tooth,  which  latter  plan  gives  very  great 
resisting  power. 

"  I 'in  and  JJ/"'<  Altai-hint  nls  In  Bicuspid*. — Although  chiefly 
applicable  to  the  incisors,  the  pin  and  plate  attachment  may  be 
successfully  combined  -with  crown  or  bar  bridges  for  molars 
and  bicuspids. 

"Fig.  484  represents  a  practical  case  in  which  the  upper  third 
molar  and  the  firsl  bicuspid  (both  without  antagonizing  teeth) 
were  utilized  for  the  attachment  of  a  bridge  made  of  gold 
crowns  with  porcelain  facings,  to  supply  the  loss  of  the  interven- 
ing teeth. 

"  Fig.  485  represents  the  case  as  prepared  for  the  bridge.  A, 
the  inner  cusp  of  the  bicuspid  cut  down  to  allow  the  placing  of 


PARTIAL  CAP  AND  PIX-BRIDOK  METHODS. 


241 


a  sufficiently  thick  crown-plate;  B,  a  cylindrical  undercut  open- 
ing between  the  cusps  tor  a  retaining-pin ;  C,  the  third  molar. 
made  uniform  in  size  from  neck  to  grinding-snrface,  the  latter 

Fig.  484. 


also  being  considerably  retrenched ;  D,  the  crown-plate  of  a 
partial  cap,  made  of  pure  gold,  soldered  with  20-carat  gold,  and 
so  constructed  as  to  cover  every  portion  of  the  tooth  except  its 

Fig.  48-3. 
D- 


buccal  surface,  the  free  edge  passing  up  under  the  gum ;  E,  a 

retaining-pin  adapted  to  the  opening  B;  F,  the  gold  cap  for  the 

molar. 

Fig.  486. 


••  Fig.  486  represents  the  bridge  anchored  in  position  with 
oxyphosphate  cement. 

16 


242 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


"  In  the  above  case  it  Avill  be  observed  that  there  is  a  con- 
siderable space  between  the  bicuspid  and  cuspid.  This  made  it 
readily  practicable  to  give  so  considerable  a  thickness  to  the 
mesial  wall  of  the  partial  cap  as  to  hold  it  securely  against  the 
side  of  the  tooth.  Had  the  space  been  less,  contact  with  the 
cuspid  would  have  afforded  the  desired  security. 


"  Fig.  487  represents  another  case  in  which  a  bridge  was  at- 
tached by  a  bar,  partial  cap,  and  retaining-pin.  A  is  an  upper 
second  bicuspid  (without  antagonist) ;  13,  its  inner  cusp,  cut 
down ;  C,  opening  for  retaining-pin ;  D,  second  molar,  with 
slot  for  bar;  E,  cuspid;  F  represents  the  partial  facing;  G,  the 
retaining-pin;  II,  a  molar  crown  of  gold,  with  porcelain  front; 
I,  a  platinum  bar  attached  to  the  crown  (II)  and  made  to  fit  into 

Fio.  4*8. 

A 


a  .-lot  (at  1);;  .1,  a  plain  plate  cuspid,  heavily  backed  and  strongly 
soldered  to  the  partial  cap,  but  left  without  attachment  to  or 
contact  with  the  cuspid. 

"  Fig.  4*8  shows  the  bridge  anchored  in  position. 

"  This  case,  alter  two  years  of  wear,  is  still  in  perfect  condi- 
tion and  doing  good  service.     As  it  was  possible  to  keep  the 


PARTIAL  CAP  AND  PIN-BRIDGE  METHODS.  243 

gold  attachments,  backings,  etc.,  out  of  sight,  the  appearance 
presented  is  very  natural. 

"  The  absence  of  antagonizing  teeth  for  the  bicuspids  in  each 
of  these  cases  was  a  favorable  condition,  as  a  considerable  thick- 
ness could  be  given  to  the  crown-plate  without  any  interference 
with  occlusion.  When  the  conditions  are  not  so  favorable, 
cutting  down  the  inner  cusp  to  the  required  extent  and  sinking 
the  opening  for  the  retaining-pin  to  the  necessary  depth  are  pro- 
cesses certainly  to  be,  as  a  rule,  preferred  to  the  entire  removal 
of  the  crown  for  the  purpose  of  ferruling  the  root  for  the  mount- 
ing of  a  crown  of  gold  and  porcelain, — a  procedure,  however, 
not  by  any  means  to  be  indiscriminately  denounced,  for  in  many 
cases  it  is  in  the  highest  degree  advisable. 

"  There  is  this  fact  to  be  considered  in  regard  to  the  use  of  the 
partial  caps  here  figured, — that  many  patients  can  be  induced  to 
consent  to  their  employment  who  would  refuse  to  submit  to 
more  radical  measures,  and  thus,  even  when  the  latter  would  be 
advisable,  the  former  may  be  employed  as  a  compromise,  or  even 
as  a  temporary  expedient.  Having  once  tested  the  advantage  of 
a  well-fitting  bridge,  the  wearer  is  much  more  likely  to  consent 
to  whatever  measures  are  necessary  to  give  it  security  and  per- 
manence." 


Fio.  480. 


FOR  SHAPING  SEAMUESS  TOOTU-ROOT  COLLARS. 


^a 


a 


03 


eq 


Ph 


a 


tt 


a, 

3 


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No.  1. 


24  I 


No.  2 


No.  3. 


No.  4. 


No.  «. 


No.  7. 


CHAPTER  XIV. 

THE    MANDREL    SYSTEM. 

In  all  styles  of  collar  crowns  the  shaping  and  adapting  of  the 
collar  is  usually  found  by  many  dentists  to  be  the  most  difficult- 
part  in  their  construction.  To  facilitate  its  performance  the 
"  Mandrel  System  "  was  introduced  by  The  S.  S.  White  Dental 
Manufacturing  Co.  The  following  is  a  revised  description  taken 
from  an  article  on  the  subject: l 

"An  examination  of  a  large  number  of  human  teeth  shows 
that,  no  matter  how  great  differences  may  exist  in  the  apparent 
shapes  of  the  crowns  of  individual  teeth  of  a  given  class,  there 
is  a  remarkable  uniformity  in  the  configuration  of  their  necks. 
That  is,  the  necks  of  upper  cuspids,  for  instance,  were  found  to 
have  a  fixed  type,  from  which  the  variations  were  very  slight  as 
to  shape,  though  there  appeared  to  be  no  exact  standard  of  size. 
So  of  the  other  classes,  with  the  single  exception  of  the  superior 
molars,  in  which  two  distinct  forms  were  found,  the  first  being 
those  in  which  the  buccal  roots  were  wrider  than  the  palatal; 
the  second,  those  in  which  the  reverse  condition  was  found,  the 
single  palatal  root  being  wider  at  its  junction  with  the  crown 
than  the  two  buccal  roots.  The  occurrence  of  roots  of  the 
second  class  being  rather  exceptional,  the  first  class  was  accepted 
as  the  type. 

"  The  configuration  of  the  necks  of  all  the  teeth  having  been 
determined,  a  set  of  mandrels  for  shaping  collars  to  fit  them  was 
devised.  The  set  (Fig.  489)  consists  of  seven  mandrels,  six  of 
which  are  double  end.  Their  shapes  are  modeled  upon  the 
general  typal  forms  of  the  necks  of  the  teeth  which  they  repre- 
sent, and  they  are  made  tapering  to  provide  for  all  required 
variations  in  size.     The  illustrations  are  about  two-thirds  actual 

1  Dental  Cosmos,  vol.  xxviii,  No.  8. 

245 


246  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

size,  the  longest  instruments  being  nine  inches  in  length.  The 
cross-sections  show  the  shapes  and  proportionate  sizes  at  the 
greatest  and  least  diameters.  The  long  taper  permits  the  most 
minutely  accurate  adjustment  of  the  collars. 

"  No.  1  is  a  double-end  mandrel,  for  superior  molars,  right  and 
left;  No.  2  is  a  single  mandrel,  for  superior  bicuspids,  right  and 
left;  No.  3  is  double-end,  for  superior  cuspids,  right  and  left; 
No.  4,  double-end,  for  superior  centrals,  right  and  left;  No.  5, 
double-end,  for  inferior  molars,  right  and  left;  No.  6,  double-end, 
for  the  inferior  centrals,  laterals,  cuspids,  and  first  bicuspids, 
right  and  left;  No.  7,  double  end,  one  end  for  the  superior 
lateral  incisors,  the  other  for  those  bicuspids  in  which  a  bifur- 
cation of  the  roots,  or  a  tendency  in  that  direction,  extends 
across  the  neck  to  the  crown  in  the  form  of  a  depression  on  one 
or  both  approximal  surfaces.  The  foregoing  scheme  compre- 
hends all  the  teeth  of  the  permanent  set  except  the  second 
inferior  bicuspids.  The  necks  of  these  approximate  those  of 
the  superior  central  incisors  so  closely  in  shape  that  it  was  deemed 
inexpedient  to  make  a  separate  mandrel,  as  the  No.  4  mandrel 
will  serve  for  both. 

"  The  collars  or  bands  are  made  seamless,  of  No.  30  (Ameri- 
can gauge)  gold  plate,  22  carats  fine.  Fifteen  sizes,  each  of 
three  widths  (T^,  T2ff,  and  T3^  inch)  are  made  (Fig.  490),  whieh  it 
i-  believed  will  cover  all  requirements.  These  collars,  although 
devised  as  a  part  of  the  system,  can  be  used  in  all  methods  of 
crown-  and  bridge-work  which  require  bands,  and  possess  many 
advantages  over  any  others.  They  are  really  labor-saving 
devices,  as  their  use  saves  the  time  and  trouble  of  making,  and 
then-  is  no  danger  of  their  coming  unsoldered  when  the  pins  or 
th<-  backing  of  the  crown  arc  being  soldered  ;  and  there  are  no 
hard  spots  to  give  trouble  in  burnishing,  as,  for  instance,  close  to 
the  root,  after  tin'  collar  has  been  shaped  and  placed  in  position, 
the  whole  surface  being  uniformly  soft. 

"The  seamless  collars  arc  also  especially  adapted  to  removable 
or  detachable  bridge-work.  They  arc  so  constructed  that  Nos. 
1,16,  and  31  exactly  tit  into  or  telescope  with  Xos.  2,  17,  and  32, 
and  -o  on  through  the  entire  set,  each  collar  fits  into  the  series 
nexl   higher;  bo  thai  ;<  root    may  be  banded  with  one  size  and 


THE  MANDREL  SFSTEM. 

Fio.  4110. 


247 


a  - 


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ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


the  size  next  larger  used  to  form  the  tube  for  the  telescoping 
crown.  AVlan  desirable,  the  '  seamless'  collar  can  be  strength- 
ened,  after  it  has  been  adapted  to  the  conformation  of  the  crown 
6< »  as  to  slide  freely  over  it,  by  investing  and  flowing  solder  over 
the  outer  surface;  or,  still  better,  by  adapting  the  next  larger 
size  of  collar  to  exactly  fit  around  the  first,  and  then  investing 

Fig.  491. 


the  two  and  soldering  them  together.  The  advantages  of  these 
I'ollure  for  this  kind  of  work,  and  also  for  the  construction  of 
'•ap  crowns,  are  obvious. 

••  The  other  appliances  specially  devised  for  this  system  are,  a 
reducing-plate  or  contractor,  a  pair  of  collar  pliers,  and  a 
hammer. 

••The  contractor  (Fig.  4H1;  contains  holes  which  are  comple- 


THE  MANDREL  SYSTEM. 


249 


mentarv  in  shape  to  the  mandrels.  The  mandrels  being  applied 
to  the  inner  circumferences  of  the  collars,  while  the  contractor 
must  admit  the  collars  themselves,  the  short  taper  of  the  holes 
in  the  contractor  necessarily  covers  a  somewhat  greater  range  of 


Fio.  492. 


size  than  is  shown  in  the  mandrels.  With  this  appliance  collars 
can  be  evenly  and  accurately  reduced  in  size  at  the  edges,  with- 
out burring  or  buckling.     The  illustration  is  actual  size. 

"  The  collar  pliers  (Fig.  492)  are  for  contouring  the  collars  to 
shape,  one  beak  being  made  convex  and  the  other  concave  to 


250 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  493. 


correspond.  With  this  appliance  the  slightest  changes  required 
in  the  contour  of  the  collars  are  easily  made.  About  a  half-inch 
from  the  extremity  of  the  concave  beak  a  small 
bar  of  flat  steel  is  attached  to  it  by  means  of  a 
screw.  The  free  end  of  the  bar  has  a  minute 
projection  upon  one  face,  the  other  being  rein- 
forced to  lit  into  the  concavity  of  the  beak.  In 
the  center  of  the  face  of  the  convex  beak  is  a 
depression,  into  which  the  projection  on  the 
steel  bar  strikes,  making  a  very  efficient  punch 
for  forming  guards  or  stops  to  prevent  the  col- 
lars from  being  forced  too  far  under  the  gum. 
The  depression  in  the  convex  beak  being 
slightly  larger  than  the  projection  or  punch, 
the  metal  is  not  cut  through,  but  merely  raised 
on  the  side  opposite  to  the  punch.  The  punch 
attachment  being  pivoted  can  be  swung  to  one 
side  when  not  in  use. 

"  Fig.  493  is  a  mallet  or  hammer,  with  steel  face 
and  horn  peen.     The  handle  is  nine  inches  long. 

"  One  of  the  appliances  required  [is  a  lead 
anvil,  which  being  only  a  piece  of  soft  lead  say 
two  by  three  inches  and  an  inch  thick  is  not 
illustrated.  The  female  die  of  an  ordinary  case 
will  answer  very  well. 

"  To  illustrate  the  uses  of  these  appliances, 
take  a  case  in  which  the  two  inferior  bicuspids 
of  the  left,  side  are  missing,  and  the  crowns 
of  the  cuspid  and  first  molar  so  badly  decayed 
that  the  probabilities  are  that  they  will  soon 
fall  victims  to  the  forceps.  The  old-time  way 
would  have  been  to  extract  the  molar  and  cus- 
pid, and  make  a  partial  plate.  Examination, 
however,  shows  that  the  roots  of  these  two  teeth 
are  in  good  condition,  affording  an  excellent 
opportunity  for  the  construction  of  a  piece  of 
bridge-work. 
"  With  a  corujldum-point  or  rotary  file,  cut  off  the  remaining 


THE  MANDREL  SYSTEM. 


251 


]. options  of  the  crowns  level  with  the  gum  margins.  Prepare 
the  roots  in  any -of  the  well-known  ways,  thoroughly  cleansing 
the  apical  portions  and  rilling  them  with  whatever  material  is 
desired,  being  careful  only  that  the  work  is  well  done.  For  the 
better  retention  of  the  filling-material  to  he  placed  in  the  pulp- 
chamber,  retaining-grooves  can  be  made  or  retaining-posts  in- 
serted. Take  a  piece  of  binding-wire  (No.  26,  American  gauge), 
two  and  one-halt' inches  long,  pass  it  around  the  neck  of  the  molar 
stump,  cross  the  free  ends,  and,  holding  the  wire  in  place  with  one 
finger,  twist  the  ends  with  a  pair  of  flat-nose  pliers  until  the  wire 
clasps  the  neck  closely  at  every  point  (Fig.  494).  Where  there 
are  any  irregularities  in  the  contour  of  the  tooth,  it  is  necessary 
to  press  the  wire  into  them  with  an  approximal  burnisher.  It  is 
obvious  that  the  ring  thus  formed  will  show  the  exact  size  and 
shape  of  the  neck  of  the  tooth.     Remove  the  ring  carefully,  lay 


Fin.  491. 


Fio.  405. 


it  on  the  lead  anvil,  put  over  it  a  piece  of  flat  metal,  and  with  a 
smart  blow  from  a  hammer  drive  the  wire  into  the  lead  (Fig. 
495).  Upon  removing  the  wire  an  exact  impression  of  the  ring 
will  be  left  in  the  lead  anvil.  (This  part  of  the  work,  as  indeed 
all  others,  should  be  done  carefully  as  described.  The  wire  ring 
may  be  driven  into  the  lead  by  a  direct  blow  of  the  hammer 
faee,  but  the  blow  might  not  strike  equally,  and  the  interposition 
of  the  flat  metal  held  level  insures  an  even  impression.  A  piece 
of  an  old  file  is  best,  as  the  file-cuts  keep  the  wire  from  slipping.) 
"Next,  cut  the  wire  ring  at  the  lap,  straighten  out  the  wire, 
and  select  a  suitable  collar  by  comparing  the  length  of  the  wire 
with  the  straight  lines  in  the  diagram  (Fig.  490)  which  show  the 
inside  diameters  of  the  various  sizes.  Should  none  of  these 
correspond  exactly,  take  preferably  the  next  size  smaller.  It  will 
be  remembered  that  the  collars  are  No.  30  in  thickness,  while 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


Fig.  49G. 


the  wire  with  which  the  conformation  is  secured  is  No.  26.  This 
difference  permits  the  collar  when  contoured  to  shape  to  enter 
the  lead  impression  readily,  a  decided  advantage  in  titting. 
Having  selected  the  collar,  fit  it  to  mandrel  Xo.  5,  with  the  peen 
of  the   hammer,  holding  it   upon  the  lead  anvil,  and  using  a 

slight  pushing  force  to  help  in 
stretching  and  forming  it  (Fig. 
496).  Having  driven  the  collar  to 
form,  remove  it  from  the  mandrel 
and  try  in  the  lead  impression. 
If  it  does  not  fit  exactly,  return 
it  to  the  mandrel  and  stretch  it  a 
little,  when  it  will  usually  fit  per- 
fectly, as  the  mandrels  have  been 
designed  carefully  to  the  average 
shapes  which  obtain  in  the  great 
majority  of  tooth-necks.  In  the 
exceptional  cases  where  the  collar 
does  not  fit  it  can  be  readily  con- 
toured to  the  exact  shape  with  a 
pair  of  flat-nose  pliers.  Of  course,  if  it  fits  the  impression  in 
the  lead,  it  will  fit  the  neck  of  the  tooth,  always  provided  the 
measurement  and  the  impression  have  been  carefully  made. 

"  If  the  collar  or  band  has  been  accidentally  stretched  too 
much,  or  if  for  any  reason  when  brought  t<>  shape  it  is  too 
large,  its  root  end  can   easily  be   reduced  to  the  proper  size  by 


Fio.  497. 


Fro.  499 


tli-'  use  of  tli';  contractor.  Place  the  edge  of  the  collar  wliieli 
is  to  fit  the  roof  in  tin-  proper  hole :  bold  it  level  with  a  piece  of 
file  as  in  taking  the  lead  impression  of  the  ring,  and  tupping 
lightly  on  the  tile  drive  the  collar  into  the  plate  (Pig.  497)  until 
the  proper  reduction  is  made.  The  collar  is  next  'festooned' 
h,  correspond  to  the  shape  of  the  maxillary  ridge.     Lay  it,  gum 


THE  MA  XI) li EL  SYSTEM. 


252 


cdu-e  up,  on  the  lead  anvil,  and  with  the  piece  of  flat  file  and 
the  hammer  drive  it  into  the  lead.  A  few  cuts  with  a  tine  halt- 
round  file  across  the  approximal  diameter  will  conform  the 
edges  to  the  surface  of  the  ridge  (Fig.  498).  Then  place  the 
collar  in  position,  and,  having  ascertained  just  how  far  it  should 
go  down  on  the  root,  remove  it,  and  with  the  small  spring  punch 
in  the  collar  pliers  form  projections  on  the  inside  of  the  band  at 
the  proper  points  to  serve  as  stops,  which,  resting  on  the  top  of 
the  root,  will  prevent  the  collar  from  being  forced  further  down 
upon  it  than  is  desirable  (Fig.  499). 

"A  collar  for  the  cuspid  is  then  fitted  in  the  same  manner, 
using  mandrel  No.  6  for  shaping,  after  which  the  case  is  ready 
for  the  building  of  the  bridge. 


Ftg.  400. 


Fia.  503. 


"  Cement  with  oxyphosphate  both  collars  in  position.  Then 
take  an  impression  of  the  parts,  including  the  interiors  of  the 
excavated  pulp-chambers,  from  which  make  a  cast  in  the  usual 
way.  Bend  a  short  piece  of  half-round  gold  or  platinum  wire 
into  the  form  of  a  horse-shoe,  the  two  extremities  of  which 
shall  fit  into  the  roots  of  the  molar.  Then  take  a  longer  piece 
of  the  same  wire,  somewhat  more  than  enough  to  extend  from 
the  toe  of  the  horse-shoe  when  in  position  to  the  cuspid  root; 
bend  one  end  of  it  at  a  right  angle,  or  nearly  so,  to  fit  the  root 
of  the  cuspid,  and  (cutting  off  any  excess  of  length)  solder  the 
other  end  to  the  toe  of  the  horse-shoe.  The  bar  extending 
between  the  two  roots  is  the  truss  of  the  bridge.  Xext,  place 
the  appliance  on  the  cast  (Fig.  500),  holding  it  in  position  with 


256 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


Mu  ilar.  The  crown  of  the  right  cuspid  is  nearly  gone,  but  the 
root  is  sound  and  capable  of  supporting  one  end  of  the  bridge. 
The  other  end  will  be  attached  to  the  second  molar,  which  is 
a  sound  tooth.  Prepare  and  band  the  cuspid  root  as  before ; 
dress  off  the  second  molar  crown  until  it  is  slightly  smaller  than 
the  neck,  and  shorter  at  the  occluding  surface,  so  as  to  permit 
a  cap  to  be  teleseoped  over  it,  and  take  the  measure  of  the 
crown  with  the  binding-wire.  Select  a  suitable  seamless  collar 
of  sufficient  width  to  extend  from  the  neck  to  a  little  beyond  the 
grinding-surface,  and  drive  it  up  on  the  proper  mandrel  to  get 
the  general  shape,  but  not  the  full  size  required  to  fit  the  tooth, 
leaving  it  so  that  the  edge  having  the  larger  circumference  will 
just  pates  over  the  end  of  the  crown;  place  the  collar  on  the 
tooth,  and  with  a  block  of  wood  and  the  mallet  tap  it  to  place 

Fig.  503. 


just  beyond  the  free  margin  of  the  gum.  This  method  will 
make  a  close  lit.  ;is  the  collar  will  readily  stretch  all  that  is 
necessary.  With  a  sharp-pointed  instrument  mark  the  length 
of  the'  crown  ami  line  of  the  gum  margin,  remove  the  collar, 
and  cut  it  to  the  proper  form  as  indicated.  Then  in  apiece  of 
-old  plate  of  the  thickness  used  for  caps  form  four  little  depres- 
> i « 1 1 1 ^  of  tin'  general  character  of  an  impression  of  the  molar 
CUSps.  Aii  easy  way  to  do  this  is  to  lay  the  plate  on  th«'  lead 
anvil;  then  with  the  ball  on  the  end  <>f  an  ordinary  socket- 
bandle  and  the  hammer  the  depressions  are  made  in  a  moment, 
('lamp  the  collar  on  the  plate,  borax  it,  charge  with    solder,  and 

heal  till  the  solder  (lows.  Cut  oft  the  surplus  plate,  and  a  per- 
fect cap  for  the  molar  i<  made.  Place  it  on  the  tooth  and  take 
an  impression,  and  thereafter  procee  I  a-  before  directed  to  make 


DET.  I  <  'II A  BLE  BRIDGE-  WORK. 


257 


the  truss  of  the  bridge  and  mount  the  teeth,  except  that  in  this 
case  the  posterior  end  of  the  truss  is  to  be  soldered  to  the  molar 
cap.  For  the  final  attachment  place  a  little  oxyphosphate  in  the 
cap  to  secure  it  firmly  (Fig.  503),  first  cutting  a  slot  in  the  crown 
end  of  the  cap  for  the  escape  of  the  excess  of  material.  Pressure 
upon  the  filling-material  hastens  its  hardening."     .     .     . 

DETACHABLE    BRIDGE-WORK. 

"  A  method  of  constructing  a  detachable  bridge  applicable 
to  cases  where  one  or  both  of  the  supports  or  piers  are  sound 
teeth  is  as  follows:  In  the  case  adduced  for  illustration  the 
right  inferior  cuspid  crown  was  decayed,  and  both  of  the  bicus- 
pids and  the  first  molar  were  absent.  The  supports  for  the 
bridge  were  the  sound  second  molar  and  the  cuspid  root.  After 
the  cuspid  root  was  prepared  and  banded,  the  crown  of  the 

Fig.  504. 


molar  was  reduced  very  slightly, — not  sufficient  to  destroy  the 
.  enamel,  but  just  enough  to  permit  a  collar  properly  fitted  to  pass 
over  it.  A  collar  somewhat  wider  than  the  length  of  the  crown 
from  grinding-surface  to  neck  was  fitted  and  cut  to  the  proper 
width.  Two  lugs  wTere  then  soldered  upon  the  anterior  and 
posterior  sides  and  bent  to  fit  into  the  approximal  fissures,  which 
were  slightly  cut  out  to  admit  them..  An  impression  was  taken, 
the  collar  coming  away  in  the  plaster,  and  a  cast  was  made  with 
the  collar  in  position.  A  coned  tube  was  then  made  for  the 
root  of  the  cuspid  and  a  coned  pin  fitted  into  it,  A  truss  of 
half-round  wire  was  made,  to  which  the  coned  pin  aud  the  molar 
collar  were  soldered  (Fig.  504).  A  half-clasp  to  grasp  the  lateral 
was  next  soldered  to  the  end  of  the  truss  to  be  supported  by  the 

17 


258 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


cuspid.  The  object  of  this  clasp  was  to  guard  against  the  teeth 
being  thrown  out  of  proper  alignment  by  the  force  of  mastica- 
tion. Bonwill  crowns  were  then  vulcanized  to  the  truss,  after 
their  supporting  pins  had  been  fitted  and  soldered  to  it.  (Counter- 
sunk crowns  can  be  used  as  well  in  the  same  way.  Plain  plate 
teeth  may  also  be  used  in  this  style  of  work,  in  which  event  they 
are  to  be  soldered  to  the  truss.)  The  bridge  was  then  ready  to 
be  set,  which  was  accomplished  in  the  following  manner:  The 
cuspid  root  was  nearly  filled  with  oxyphosphate,  and  the  coned 
tube  was  placed  upon  the  pin.  The  band  was  put  on  the  molar, 
and  the  coned  pin  with  the  tube  upon  it  was  forced  into  the 
plastic  in  the  cuspid.  As  soon  as  this  became  set,  the  tube  was 
held  permanently,  while  the  bridge  itself  could  be  removed 
whenever  desired.  (Fig.  505). 

Fig.  505. 


"This  method  of  fixing  the  tube  allows  considerable  range  in 
its  adjustment.  In  soldering  the  coned  pin  to  the  truss,  care 
should  be  taken  to  set  it  at  an  angle  exactly  parallel  to  the  axis 
of  the  molar;  otherwise  there  will  be  difficulty  in  removing  the 
bridge. 

"A  second  style  of  detachable  bridge-work  to  be  described 
involves  the  use  of  cusp  crowns  (Fig.  506)  for  supporting  posts 
or  piers.  Suppose  a  case  where  a  bridge  is  required  to  extend 
from  the  right  inferior  cuspid  to  the  right  inferior  second  molar, 
with  only  the  root-  of  the  two  teeth  named  as  supports.  Prepare 
the  roots  and  pulp-chambers.  Set  screw-posts  into  the  dentine 
for  anchorage  or  as  retaining-pins,  and  fit  the  collars,  using  sizes 
wide  enough  to  form  the  walls  of  the  crowns.  Fill  the  pulp- 
ehamber  and  cement  on  the  collars,  filling  about  two-thirds  of  the 


DETACHABLE  BRIDGE- WORK. 


259 


depth  of  the  collars  with  a  plastic  filling-material,  packing  it  well 
around  the  retain ing-poste;  Select  Buitable  cusp  crowns  for  the 
molar  and  cuspid,  and  place  them  in  the  ends  of  the  hands  to 
ascertain  the  occlusion.  If  too  long,  shorten  the  cusps  or  reduce 
the  bands  with  engine  corundums  or  rotary  files,  and  when  the 
correct  articulation  is  found  form  a  small  square  shoulder  in  the 
lingual  edge  of  the  cuspid  and  in  the  posterior  grinding-surface 
of  the  molar.  Fill  the  remaining  portion  of  the  collars  with 
plastic  mixed  somewhat  thinner  than  the  first  lot,  and  set  the 
cusp  crowns  in  position.  If  there  are  antagonizing  teeth  the 
mere  closing  of  the  patient's  jaws  will  force  the  crowns  to  place. 
If  there  are  no  antagonizing  teeth  the  crowns  can  be  readily 
tapped  to  place  with  the  mallet,  using  a  piece  of  wood  as  a 
driver.  Allow  the  filling-material  to  set  firmly,  trimming  off 
any  excess  which  may  exude  around  the  collars. 

Fig.  506. 


"  Bridge  supports  or  piers  constructed  on  this  plan  are  strong 
and  durable,  and  likely  to  withstand  any  strain.  Take  an 
impression,  and  proceed  to  fit  seamless  collars  to  telescope  over 
those  already  set  upon  the  cuspid  and  second  molar  roots.  It 
will  be  remembered  that  these  collars  are  so  made  that  each  size 
telescopes  into  the  next  higher  series.  If  the  proper  sizes  are 
selected  for  the  outside  or  female  bands,  the  work  of  fitting  is 
readily  and  quickly  accomplished,  forming  tubes  which  slide 
easily  over  the  supporting  piers,  and  at  the  same  time  fit  closely. 
It  is  only  necessary  to  take  care  in  shaping  the  tubes  not  to  drive 
them  too  far  up  on  the  mandrels  and  thus  stretch  them  so  as  to 
destroy  the  fit.  To  the  outer  end  of  each  of  the  tubes  solder  a 
small  piece  of  gold  plate,  forming  partial  caps  so  placed  as  to 
rest  when  in  position  upon  the  shoulders  previously  cut  in  the 
cusp  crowns.  Adjust  a  truss  bar  of  half-round  gold  wire,  to  the 
ends  of  which  solder  the  tubes.     The  truss  is  now  readv  for  the 


260 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


teeth,  which  may  be  of  any  of  the  forms  used  for  this  purpose, 
and  they  may  be  attached  to  the  bar  in  any  way  desired.  One 
of  the  strongest  attachments  is  vulcanite.  Fig.  507  shows  the 
construction  and  the  finished  case. 

Fig.  507. 


"An  easy  modification  of  the  plan  just  described  is  readily- 
adapted  to  cases  where  only  a  small  space  is  to  be  tilled  and  one. 
end  of  the  bridge  is  to  be  supported  by  a  sound  tooth.  Thus, 
suppose  it  is  desired  to  bridge  a  space  formerly  occupied  by  the 
two  inferior  left  bicuspids,  the  crown  of  the  first  molar  being  a 
mere  shell.      The  operation  would  be  essentially  the  same  as  in 


Pro   508. 


Fig.  509. 


the  previous  case, except  that  the  sound  cuspid  would  be  utilized 

one  of  the  piers  ad  follows:    Fit  a  seamless  collar,  cut  out  a 

portion  of  it  BO  that  it  will  embrace  only  about  two-thirds  of  the 

rn,  and  Bolder  a  partial  cap  .or  cover  to  it,  as  illustrated 


DETACHABLE  BRIDGE-WORK.  261 

in  Fig.  508.     Or,  if  deemed  preferable,  the  cuspid  may  be  separ- 
ated from  the  lateral  incisor  with  the  corundum-disk  and  the 

collar  allowed  to  embrace  the  whole  crown. 

"  A  crown  broken  from  a  bridge  constructed  by  any  of  the 
methods  above  described  can  be  easily  substituted,  and  the  piece 
when  repaired  will  be  as  strong  and  serviceable  as  it  was 
originally. 

Fig.  510. 


"  It  has  not  been  deemed  necessary  to  detail  the  construction 
of  a  single,  crown  separately,  as  all  the  steps  are  included  in  the 
building  of  bridges,  which  have  been  described  minutely.  Por- 
celain cusps  of  the  general  form  illustrated  in  Fig.  509  have  been 
designed  specially  for  these  cases.  In  mounting  them  the  gold 
band  is  cut  away  on  the  buccal  side  as  shown  in  Fig.  510  to 
permit  the  porcelain  to  show." 


CHAPTER  XV. 

PORCELAIN   BRIDGE-WORK. 


For  an  ideal  piece  of  bridge-work  that  will  dispense  with  the 
objectionable  features  of  a  permanently  attached  bridge  and 
refute  the  most  forcible  arguments  against  the  system,  porcelain 
is  the  most  suitable  material  known. 

DR.   BROWN'S    METHOD. 

Dr.  E.  Parmly  Brown,  of  Elustoffg,  N.  Y.,  has  invented  and 
introduced  a  method  of  porcelain  and  iridio-platinum  bridge- 
work,  which  possesses  special  merit. 

The  advantages  claimed  for  it  as  a  method  of  bridge- work  are 
as  follows : 

It  is  formed  entirely  of  porcelain  with  an  iri#ro-platinum  bar 
rumrrrrg  through  the  denture  as  a  sustaining  shaft,  thus  presents 
4rrg  a  perfect  continuity  of  porrohviti  surface. 

It  is  unaffected  by  any  chemical  action  or  condition  in  the 
moutb^It  has  no  so-called  self-cleansing  spaces,  because  none 
tfP^—~-JffGr<j<  |  u  i  r<  ■(  1 . 

A  benign  and  natural  form  of  contour  is  presented  on  its 
palatal  Burfacej^as  the  base  of  each  tooth  presses  tightly  onto  the 
membranes  of  the  gum,  which  closes  or  hugs  closely  around  i 

AihI  lastly,  it  has  the  merit  of  simplicity  of  construction  in 
comparison  with  the  other  methods  in  practice. 

Construction. — The  bridge  is  formed  by  spanning  intervening 
-paces  between  certain  natural  teeth  or  roots  with  artificial 
porcelain  substitutes  baked  onto  an  iridio-platinum  bar  J  either 
or  both  ende  of  the  bar  bring  anchored  in  a  crown,  or  hra  filling 
inserted  in  the  approximal  portion  of  the  adjoining  tyroth.  The 
root-  to  he  crowned  and  n-<'i|  as  foundations  tor  the  bridge  are 
prepared  as  for  single  crowns.     If  the  end  of  the  bar  is  to  be 

2r,2 


(M    cLu-t^1*-*-*,   r^.    r-ft^  Vr^*<£*  JU^U 


PORCELMS  BRIDGE-  WORK. 


263 


fixed  in  a  natural  tooth,  the  cavity  thijit  is  to  receive  and  anchor 
it  is  opened  up  sivtfi.civ.ut.-Xu  admit  it,-*in-4be-breuspids  and  mo- 
lars, from  the  grinding-surfaee  to  tin-  oervieo-approximal  edge, 
and  in  the  incisors,  on  the  approximal  side,  with  an  opening  on 
the  palatal  or  lahial  face,  as  indicated.  A  square  bar  of  iridio- 
platinum  wire  from  No.  13  to  No.  15,  U.  S.  standard  gauge,  in 
thickness,  is  fitted  cither  to  the  cavities  of  the  teeth  in  which  it  is 
to  be  anchored,  or  bent  and  fitted  in  any  devitalized  tooth  or  root 
which  is  to  act  as  an  abutment,  The  end  of  the  wire  that  forms 
the  post  is  pointed  and  introduced  well  up  the  root-canal,  and 
the  end  forming  the  bar  is  slightly  flattened  or  squared.  Any 
intervening  root-posts  are  fitted  and  riveted  to  the  bar  as  it 
passes  above  them.      «*'  "~  "*" "■""- 

T-t*=tyg=har-  the  toeTirawA,  whiehaire  ordinary  Fig.  611. 
plate  teeth,1  are  fastened ^^  in cisoRT/by  slightly 
flattening  the  bar  and  riveting  them  fast,  or  when 
straight-pin  teeth  are  usedjhx  bending  the  pins 
over  the  bar  (FigO  511);/uicuspids  and  molars 
with  straight  pins,  by  grinding  a  slot  with  a  disk 
between  the  pins  and  bending  them  over  the  bar_;  jwhich  i 
slightly  barbed  and  set  in  the  slot.  ^  ''  ■•■  >j r    ' ,     "  T 

.  '■£         I,'..     j»    .      '  AD"'    **t 

The  proper  position  of  each  tooth  having  been  determine 

adjustment  in  the  mouth,  or  to  the  articulating  model,  the  rivets 

and  bar  on  each  tooth  are  carefully  filled  around  and  the  cervico- 

palatal  portion  rounded  off"  with  porcelain  body  so  as  to  present 

a  natural  surface  to  the  tongue.  \The  shape  of  the  end  of  the 

root  is  given  to  the  crown  by  placing  the  porcelain  body,  to 

which  a  small  quantity  of  starch  has  been  added,  around  the 

post  as  it  is  fixed  in  position  on  the  model ;  the  plaster  having 

been  previously  varnished  with  collodion  to  prevent  cohesion. 

The  spaces  between  the  teeth  on  the  line  of  the  bar  are  to  be 

substantially  joined  with  the  porcelain  body;  free  spaces  between 

the  teeth  at  the  cervical  portion  are  to  be  preserved  as  much  as 

possible  without  interfering  with  strength  or  producing  places 

that  will  be  uncleanly. 

. L— — ~ ._,- 

1  Dr.  Brown  uses  T-be-S^-W-hit  j  Dental  Mt'g.  Co.'s  teeth  entirely  for  this  work, 
as  he  has  found  them  the  most  suitable,  being  the  only  kind  that  will  retain  their 
color  in  the  intense  heat  to  which  they  are  subjected. 


264 


ARTIFICIAL  CROU'X-  AXD  BRIDGE-WORK. 


-       /  OC 


The  bridge  is  then  placed  on  a  slide  in  the  muffle  of  a  con- 
tinuous-gum furnace.  It  is  sustained  in  position  by  inserting 
the  pins  in  holes  drilled  in  the  slide  (Fig.  512)  or  by  suspending 
it  with  platinum  wire  between  two  platinum  posts  inserted  in 
the  slab.  The  bridge  is  then  baked  the  same  as  continuous-gum 
work.  It  is  next  fitted  to  the  mouth.  If  any  alterations  are 
required  they  should  be  made,  or  if  any  imperfections  in  the  body 
occur  the  places  should  be  filled  in  and  the  bridge  again  baked. 
It  is  then  ready  for  insertion. 

,,  v,  rtion. — When  the  bridge  is  supported  by  crowns  alone,  the 
posts  are  barbed  and  the  bridge  is  then  cemented  on,  the  same  as 
any  other.  If  one  end  is  supported  by  a  porcelain  crown  and 
the  other  by  a  bar,  the  filling  on  the  bar  end  is  inserted  up  to  the 

Fro.  512. 


positron  the  bar  is  to  occupy  before  fastening  the  post  of  the  crown 
end,  wuich  is  thm  cemented  and  the  filling  of  the  bar  end  com- 
pleted, ylt'  both  ends  are  bars,  both  fillings  are  inserted  up  to 
the  position  of  the  bars,  the  bridge  inserted,  and  the  fillings 
liui-hed;  the  bridge  being  held  by  an  instrument  or  the  fingers 
until  tie-  hat  ends  a£fi  partly  covered. 

When  ifold  is  used,  the  rubber-dam  should  first  be  applied, 
and  tli.'  cervical  porEdn  of  the  teeth  of  the  bridge  nresstfd' 
tightly  into  it  to  avoid  any  spSQg  bring  left  after  it*  removal  and 
the  completion  of  the  operation. 

When  amalgam  in  useel^the  rubber-dam  is  not  noffftjfiary 
Tn    Fig.  513,  No.  1    is   a   third    molar,  pulp  alive,  with   large 
filling;    No.  2  ifl  a  porcelain   bridge;   Xo.  :',  is  a  first  molar,  pulp 
dead,  with  a  metal  bar  entering  the  pulp-chamber. 


PORCELAIN  BRIDGE-WORK. 


265 


Iii  Fig.  514,  No.  1  is  a  second  molar,  pulp  alive,  with  a  crown 
filling  of  gold  or  amalgam  retaining  the  bar  ;  Xo.  2  is  a  porce- 
lain bridge;  Xo.  3  is  a  gold  crown  with  bar  passing  through 
one  side  of  the  crown  into  the  root. 

Fig.  515  is  a  view  of  a  bridge  of  two  teeth, — a  central  porce- 


Fig.  513. 

1  2  3 


Fig.  515. 


i  2        ;i 


lain  crown  with  a  lateral  baled  onto  it,  the  bar  and  pin  being  of 
the  same  piece,  bent  at  about  a  right  angle.  Xo.  1  is  a  porcelain 
crown  forming  part  of  the  bridge  ;  Xo.  2  a  bridged  lateral  with 
metal  bar  baked  through  it;  Xo.  3  a  living  cuspid  with  a  metal 
bar  running  into  the  center  of  a  solid  gold  filling. 


Fig   516. 


Fig.  518. 


Fig.  517 


Fig.  516  is  a  view  of  a  central  incisor  bridged  onto  two  teeth 
whose  pulps  have  been  lost. 

Fig.  517  is  a  view  of  an  extension  bridge  consisting  of  a  right 
central  and  left  lateral,  supported  by  a  left  central  tooth  or  crown 


266 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


as  the  case  may  be.     The  bar  can  be  anchored  in  a  filling  in  the 

natural  crown  or  attached  to  the  artificial  one.  Nos.  1  and  3 
are  teeth  on  a  porcelain  bridge;  No.  2  the  natural  tooth  or  arti- 
ficial crown  on  which  the  bridge  is  saddled. 


Fio.  519. 


Fio.  520. 


Figs.  518,  519,  and  520  represent  a  bridge  of  eleven  teeth 
recently  inserted  by  Dr.  Brown  on  two  cuspid  roots,  a  pulpless 
molar  on  the  left  side  which  was  capped  with  a  gold  crown, 


Fig.  521. 


thn>:i'_rh  the  side  of  whi  :!i  thy  bar  was  passed  and  anchored  in 
the  root,  and  a  molar  on  the  right  side  into  which  the  other  end 
of  the  bar  was  anchored  in  a  gold  filling. 


PORCELAIN  BRIDGE-  WORK. 


267 


Fig.  521  represents  a  bicuspid  bar-bridge  anchored  in  the  molar 
and  first  bicuspid.  The  side  cut  shows  the  construction.  This 
operation  was  performed  by  Dr.  Brown  for  Dr.  Win.  Crenshaw,  of 
Atlanta,  Georgia,  at  the  anniversary  clinic  of  the  First  District 
Dental  Society  of  the  State  of  New  York,  in  January,  1887. 
^/Fig.  522  represents  an  extension  bridge  in  which  the  abut- 
ment consists  of  a  crown  and  bar  combined. 


Fig.  622. 


Fig.  523. 


Fig.  523  represents  an  extension  bar-bridge.  The  filling  in 
the  second  bicuspid,  which  extended  from  the  mesial  to  the 
distal  side,  had  been  inserted  some  time  previously.  Enough  of 
the  gold  was  removed  from  the  mesial  section  of  the  filling  to 


Fig.  524. 


admit  the  bar,  which  was  then  securely  anchored  and  the  filling 
restored  to  its  original  form.  The  operation  was  performed  by 
Dr.  Brown  for  Dr.  F.  P.  Hamlet,  and  to  present  date  has  been 
worn  £hree  years.  The  antagonizing  teeth  in  the  act  of  occlusion 
favor  the  artificial  tooth  forming  the  bridge. 


i  f\  ) 


268 


ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 


In  porcelain  bridge-work,  should  a  case  require  it,  artificial 
gum  in  a  moderate  amount  can  be  formed  above  the  teeth  of 
thi-  bridge,  to  restore  the  contour  of  the  parts.  Figs.  524  and 
525  illustrate-  a  case  of  this  character.     A,  Fig.  526,  shows  the 

Fig.  525. 


labial   and  13  the  lingual  aspect  of   the  incisor  bridge  before 
insertion. 


n  filllllTng  thWWtTlr   nt'pn™"'^"    hrirlgn    ii»1i«»ii  it\u  r.nim'uliirur*- 

Fio.  627. 


fgrable  t"  cap  1 1  j < -  pots,  plat 
the    piiTrpe^  :i-  '1  ■-  nbt*Lat 
\<>  the  ends  of  roe  roots 
illustrated  in  Cig.  ~>-~t.     ( 'ap 


PORCELAIN  BMDQE-WOItK. 


269 


with  a  vi 

the  "rTndge  continued. 

Fig.  i>W5  represents  a  case  WBBG&y  restored  by  Dr.  Brown's 
method  by  Dr.  M.  L.  Rhein,  of  New  York.  To  remedy  the 
abnormal  character  of  the  occlusion,  the  lower  anterior  teeth 
and  the  right  upper  cuspid  were  trimmed  to  the  dotted  line  seen 

Fig.  528. 


in  the  figure.  To  replace  the  missing  teeth  porcelain  bridge- 
work  was  then  constructed.  The  lateral  and  central  roots,  and 
the  right  cuspid  and  the  molar,  constituted  the  abutments.  On  the 
central  and  lateral  roots  were  mounted  caps  with  collars.  A 
platinum  crown  was  then  made  for  the  cuspid  (Fig.  529),  and  to 
this  crown  was  attached  the  bar,  which  was  extended  to  its 
anchorages  in  the  molar  crown  and  the  lateral  and  central  roots, 


Fig.  529. 


Fig.  530. 


the  caps  on  the  ends  of  which  the  posts  pierced.  Owing  to  the 
large  quantity  of  porcelain  body  to  be  used  in  forming  the  artificial 
gum,  a  strip  of  platinum  plate  was  extended  above  the  bar  to 
stiffen  its  projecting  ends  and  prevent  warpage  in  baking.  The 
artificial  teeth  were  then  articulated  to  meet  the  incisive  edges  of 
the  inferior  natural  teeth,  and  thus  in  a  measure  overcome  the 
deformity  caused  by  the  abnormal  occlusion.     In  doing  this  the 


270 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


labial  aspect  of  the  cuspid  was  covered  by  the  artificial  teeth.  Por- 
celain gum  was  then  formed  above  the  teeth  in  sufficient  quantity 
to  restore  the  contour  of  the  part?.     It  was  brought  to  a  feather 

Fig.  531. 


edge  and  pressed  hard  against  all  the  tissues  to  insure  a  hygienic 
condition.  Fig.  530  shows  the  finished  bridge.  In  Fig.  531 
the  bridge  is  seen  in  position.     The  artistic  result  and  improved 

Fio.  532. 


appearance  effected  are  at  once  apparent.     The  mechanical  con- 
struction of  the  piece  was  intrusted  to  Dr.  C.  L.  Andrews. 


PORCELAIN  BRIDGE-WORK. 


271 


Figs.  532  and  533  represent  an  upper  and  lower  case  of  por- 
celain bridge-work,  inserted  by  Dr.  Wm.  Crenshaw,  in  which 
several  roots  and  teeth  were  used  to  form  the  necessary  abut- 
ments. The  upper  section  anteriorly  receives  the  combined 
support  of  several  roots  as  illustrated  in  Fig.  532.  The  bar  on 
the  left  side  is  made  flat  and  hooked  on  the  end,  affording  a 
secure  means  of  anchorage.  A  gold  crown  forms  the  support  on 
the  right.      The  lower  section  is  firmly  supported  on  the  right 

Fig.  533. 


side  by  passing  the  bar  through  the  cuspid  and  inserting  the  end 
in  the  pulpless  bicuspid  as  illustrated  in  Fig.  533.  The  pulpless 
bicuspid  on  the  left  constitutes  the  other  abutment. 

Dr.  Brown's  system  and  method  of  bridge-work  compares 
with  other  forms  of  bridge-work  as  continuous-gum  work  com- 
pares with  other  form?  of  plate-work.  Its  cleanliness,  through 
the  unalterable  character  and  continuity  of  its  sur&ce  and  the 
incorruptibility  of  the  material,  rwnde-*'fl  it  , a 'Superior  form  of 
d^wtaw.  The  ultimate  value  of  this  method,  however,  as  a 
means  of  replacing  lost  members  of  the  dental  arch,  depends, 
like  others,  on  its  proper,  correct,  and  skillful  application  to 
casesc.suitable  for  it. 


u- 


tXx\.t- 


;■ 


CHAPTER  XVI. 

CROWN-  AND    BRIDGE-WORK    COMBINED   WITH    OPERATIVE 
DENTISTRY    IN   DENTAL   PROSTHESIS. 

The  combination  of  operations  on  the  natural  teeth  with  crown- 
and  bridge-work  affords  extraordinary  advantages  in  dental 
prosthesis.  The  results  which  can  be  accomplished  commend 
the  plan  strongly  to  the  experienced  practitioner.  A  few  cases 
are  adduced  in  illustration. 

In  the  case  presented  in  Fig.  53-4  the  operative  procedures  were 
confined  to  the  upper  jaw,  the  lower  teeth  of  the  patient  being 

Fig.  534. 


in  good  condition.  The  bicuspids  and  the  first  and  second 
molars  of  both  sides  of  the  upper  jaw  bad  been  lost  many  years 
before,  and  the  incisors  and  cuspids  showed  the  effects  of  extensive 
abrasion.  The  occlusion  was  sustained  and  the  principal  part 
of  mastication  performed  by  the  incisors,  as  the  third  molars  had 
been  forced  backward  and  antagonized  only  very  slightly  on  one 
side. 

272 


OPERA  TIVE  DENTISTRY  WITH  CRO  WN-  AND  BRIDGE-  WORK.      273 


The  patient,  a  gentleman,  had  had  a  plate  inserted,  to  the  pres- 
ence of  which  he  had  vainly  endeavored  to  accustom  his  mouth. 
The  abrasion  of  the  incisors  and  cuspids  was  of  the  rapidly  pro- 
gressive character.     These  teeth  were  contoured  with  gold  foil  to 


Fig.  535. 


the  form  shown  in  Fig.  535,  and  a  wire  post  was  inserted  in  the 
right  lateral,  which  was  pulpless.  At  the  occludingsection  of  each 
filling,  the  layer  of  gold,  after  being  packed  with  the  plugger, 
was  additionally  condensed  and  hardened  with  a  Herbst  agate- 

Fig.  536. 


point  burnisher  to  enable  it  to  better  resist  the  aggressive  force 
of  the  lower  teeth.  The  third  molars  were  capped  and  length- 
ened with  gold  crowns,  the  lines  of  their  sides  being  made 
parallel,  to  admit  of  a  proper  adjustment  of  the  supporting  collars 

18 


274 


ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 


for  a  removable  plate  bridge,  by  adding  gold  on  their  external 
surfaces.  The  plate  bridge  was  employed  because  of  the  space 
between  the  abutments,  which  suggested  the  idea  of  utilizing 
the  alveolus  to  assist  in  supporting  it.  A  narrow  shoulder  was 
formed  on  each  crown  to  support  the  collars.  The  attachments 
to  the  cuspids  rested  by  means  of  a  little  shoulder  on  the  occlud- 
ing portions  of  the  fillings  inserted.  Fig.  535  shows  the  com- 
pleted denture,  and  Fig.  536  an  anterior  view  of  the  same.     ) 

Fig.  537. 


In  the  case  illustrated  in  Fig.  537,  the  patient,  a  lady,  had 
previously  worn  a  plate,  the  clasp  of  which  had  entirely  abraded 
the  sides  and  cervix  of  the  right  cuspid  of  enamel,  and  caused 
recession  of  the  margin  of  the  investing  gum.  The  decay  which 
followed  the  abrasion  extended  in  a  circle  around  the  tooth.  As 
the  patient  objected  to  crowns  of  any  kind  being  applied  to 
either  of  the  cuspids,  the  decay  was  removed  and  the  edges  of 
ili''  cavity  given  a  retaining  form.  A  gold  filling  was  then  intro- 
duced  in  three  Bections,  two  of  which  embraced  the  approximal 
and  palatal  -ides,  while  the  third  surrounded  the  labial  wall, 
joining  the  other  two  sections  at  that  point,  the  tine,,  thus  com- 
pletely encircling  the  tooth  with  gold.  A  portion  of  the  filling 
was  broughl  over  the  edges  of  the  cavity  to  better  shape  the 
tooth  for  the  attachment  to  be  applied  and  also  to  protect  the 
rides  from  future  injury.  When  this  operation  was  completed, 
the  tooth  presented  \>-vy  much  the  appearance  of  having  had  a 


OPERA  TI I  rE  DENTISTR  Y  WITH  CRO  WN-  A  ND  BRIDGE-  WORK.      275 

Close-fitting  shell  crown  applied.  Gold  fillings  were  introduced 
in  the  palatal  and  approxiraal  surfaces  of  the  left  cuspid,  to  pro- 
tect it  from  the  attachment.  Gold  crowns-were  placed  upon  the 
molars,  one  of  which,  the  left,  was  pulpless.  The  appearance 
of  the  teeth  after  these  operations  is  shown  in  Fig.  538. 

Fig  538. 


A  plate  bridge  (Fig.  539)  was  then  constructed,  the  attachments 
for  which  were  collars  on  the  molars,  and  half-collars  or  clasps 
on  the  cuspids.  The  former  rested  on  shoulders  formed  on  the 
gold  crowns,  and  the  latter  on  the  palatal  curves  of  the  cuspids. 


Fig.  539. 


Fig.  540  illustrates  a  case  as  presented  for  treatment  to  Dr. 
H.  A.  Parr.  The*  loss  of  the  posterior  teeth  of  the  lower  jaw 
and  the  abrasion  of  the  anterior  teeth  had  resulted  in  the 
abnormal  occlusion  shown.      The  incisive  edsres  of  the  lower 


fc^  /  rr  *j 


276 


ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 


teeth  were  lengthened  with  gold  contour  fillings.  Gold  collar 
crowns. with  porcelain  fronts  were  placed  on  the  upper  anterior 
teeth,  to  lengthen  them  sufficiently  to  restore  the  occlusion.  The 
upper  molars,  which  were  all  more  or  less  decayed  and  broken 
down,    were  restored  in  form  with  gold  crowns.      The  space 


Fig.  540. 


I  I  TT  "M 


representing  the  loss  of  the  left  bicuspid  was  filled  with  a  bridge 
tooth  having  a  porcelain  front,  attached  to  the  approximal  gold 
crown.     In  the  lower  jaw  a  partial  set  was  inserted  on  each  side 


Fig.  511. 


to  substitute  the  losl  posterior  teeth.    Fig.  541  Bhows  the  appear- 
ance of  the  case  when  completed. 

'i'li«:  following  case  is  a  marked  illustration  of  extensive  con- 
tour filling  combined  with  gold  and  porcelain  crown-work.  The 
operation-  were  performed  by  Dr.  E.  I'.  Brown,  with  the  excep- 
tion of  the  porcelain  inlays,  which  were  inserted  by  Dr.  C.  If. 
Land.  Pig.  542  represents  the  case  before  treatment  The  teeth 
show  the  effects  of  erosion,  abrasion,  and  decay.     The  upper 


OPERATIVE  DENTISTRV  WITH  CROWN-  AND  BRIDOE-WORK.      277 

teeth  at  the  incisive  and  palatal  portion  were  contoured  with 
rolled  gold,  No.  60,  condensed  with  the  Bonwill  electric  mallet. 

Fig.  542. 


Fig.  543. 


A  porcelain  crown  was  placed  on  the  root  of  the  left  cuspid,  and 
a  gold  crown  on  the  first  left  bicuspid.     The  eroded,  decayed, 


•J 7 s  A  R TIFICIAL  CRO  WN-  . I XD  BRIDGE-  WORK. 

and  abraded  portions  of  the  other  bicuspids  were  contoured  with 
gold.  The  treatment  of  the  lower  teeth  consisted  in  contouring 
with  gold  the  abraded  occluding  surfaces  of  the  right  first  and 
second  bicuspids  and  left  first  bicuspid.  The  left  second  bicuspid 
and  two  right  molars  were  crowned  with  gold.  The  cervical 
decay  which  affected  the  inferior  right  lateral,  cuspid,  and  first 
bicuspid  and  left  cuspid  was  removed  and  inlaid  with  sections 
of  porcelain  colored  with  gum  enamel  at  the  line  of  the  gum 
margin  by  Dr.  Land.  Fig.  543  shows  the  superior  arch  from 
the  palatal  aspect  when  completed.  Fig.  544  is  a  labial  or  front 
view  of  the  several  operations.1 

JThe  patient,  Dr.  W.  I.  Thayer,  exhibited  these  operations,  nearly  complete  d, 
at  the  clinic  of  the  First  District  Dental  Society  of  New  York,  February,  1889. 


PART  IV. 

MATERIALS  AND  PROCESSES  USED  IN  CROWN-  AND 
BRIDGE-WORK. 


CHAPTER  I. 

PLATE  AND  SOLDERS. 

Plate. — In  the  construction  of  crown-  and  bridge-work,  gold, 
platinum,  or  iridio-platinum  is  used  in  the  following  forms  and 
grades  in  carat,  as  suits  the  requirement  of  the  case  and  the 
preference  of  the  dentist : 

Gold  plate,  24  carats,  from  No.  3t)to  No.  34  U.  S.  standard 
gauge,1  for  constructing  the  collars  and  caps  to  collars  of  crowns 
and  seamless  crowns,  and  for  backing  porcelain  fronts. 

Gold  plate,  slightly  alloyed, — about  23  carats  tine, — in  crown- 
work,  if  less  flexibility  of  the  metal  is  required. 

Gold  plate,  22  carats,  No.  3$  to  No.  3j| -standard  gauge,  in 
constructing  collars  for  crowns  with  porcelain  fronts  and  all-gold 
crowns  made  in  sections. 

Gold  plate,  20  carats,  in  construction  of  bridge-work. 

Gold  for  constructing  collars  should  be  of  as  high  a  carat  as  ^uJJL**- 
possible,  to  better  resist  the  action  of  acids.  A  large  proportion  /  ojfu*-  < 
of  copper  as  an  alloy  is  objectionable,  owing  to  its  tendency  to 
cause  tarnishing  of  the  collar  where  an  acid  condition  of  the 
saliva  exists.  For  this  reason,  U.  S.  gold  coinyso  much  used  for 
collars,  is  not  quite  suitable.  It  is  also  too  stiff,  and  collars  made 
of  it  are  not  readily  burnished  to  fit  at  the  edges.  Dr.  J.  J.  R. 
Patrick's  formula,  which  is  equal  parts  of  coin  and  pure  gold, 
affords  a  plate  which  is  decidedly  preferable,  inasmuch  as  the 
proportion  of  copper  is  grestiy  reduced,  ^v   5  ju* 

Gold  plate,  24  carats,  with  a  very  thin  lining  of  platinum  or 
iridio-platinum  plate,  can  be  used  in  any  of  the  processes  con- 
nected with  crown-  and  bridge-work,  and  is  especially  recom- 
mended to  the  inexperienced,  for  the  reason  that  the  melting  of  a 
part  of  a  crown  in  the  soldering  process  is  prevented  by  its  use. 

1  The  United  States  standard  is  the  only  gauge  referred  to  in  the  original 
descriptive  matter  of  this  treatise. 

281 


282  ARTIFICIAL  CROWN-  AND  BRIDGE-WORK. 

It  is  formed  by  placing  together  an  annealed  gold  plate  and  a  plat- 
inum plate  (the  gold  about  Xo.  20  gauge  and  the  platinum  No. 
30)  and  passing  them  through  a  rolling-mill,  in  which  process  the 
plates  are  welded  and  reduced  to  the  desired  thickness. 

Platinum  and  iridio-platinum  plate  is  used  for  forming  crowns 
for  use  in  connection  with  porcelain  bridge-work.  Iridio-plat- 
inum plate  for  forming  small  collars  need  not  be  over  Xo.  35 
American  gauge.  At  this  thickness  it  can  be  easily  adapted  to 
the  cervix  of  the  tooth. 

Pure  platinum  rolled  very  thin  is  used  for  forming  caps  to 
collars,  backing  teeth,  and  for  various  purposes  connected  with 
this  class  of  operations.  Iridio-platinum  wire  is  used  for  pivots, 
pins,  or  posts,  being  more  rigid  than  pure  platinum.  A  wire 
of  gold  and  platinum  alloy  is  used  on  account  of  its  elasticity 
for  split  or  spring  pivots  or  posts  in  removable  bridge-work. 

Solders. — Gold  solder,  22  carats  fine,  is  used  for  crown-work; 
20  carats  for  crown-  and  bridge-work. 

18  carats  is  used  for  crown-  and  bridge-work,  but  this  is  con- 
sidered by  some  too  low  a  carat. 

14  carats  for  strengthening!;  seamless  crowns:  used  onlv  in 
crowning  operations. 

Successive  grades  of  solder  from  hard  to  easy  flowing  can  be 
used  in  the  regular  soldering  of  crown-  and  bridge-work ;  gold 
plate  or  a  hard-flowing  solder  for  the  first,  a  medium-flowing  solder 
for  the  next,  and  an  easy-flowing  one  for  the  finish.  This  avoids 
melting  or  flowing  of  the  gold  at  any  point  previously  soldered. 

Any  grade  of  solder  can  be  made  according  to  the  following 
formula: 

Zinc,  1^  grs.  ; 
Pure  gold, 

Silver  solder,  in  quantity  sufficient  to  make  up  the  22J 
remaining  parts  in  weight. 

The  quantity  of  silver  solder  used  will  regulate  the  grade  in 
carat  of  the  Bolder.     Thus  : 

Zinc,  1$  grs.  ; 
Pure  gold,  20  grs.  ; 
Silver  solder,  3  grs., 

will,  by  the  burning  out  of  a  portion  of  the  zinc  in  the  process, 
make  a  -older  about  20  carats  fine. 


PLATE  AND  SOLDERS.  ;>.; 

By  lessening  the  proportion  of  zinc  from  1£  grains  to  1  grain, 
the  proportion  of  silver  solder  being  kept  the  same,  the  solder 
will  become  harder-flowing  and  a  little  finer. 

Dr.  W.  H.  Dorrance  recommends  the  following  formula  as  an 
alloy  for  the  formation  of  different  grades  of  gold  solders,  the 
proportion  of  the  alloy  used  determining  the  melting  point  and 
fineness  in  carat  of  the  solder: 

1  part  pure  silver  ; 

2  parts  pure  zinc  ; 

3  parts  pure  copper. 

The  silver  and  copper  are  first  melted  together  in  a  crucible 
lined  with  borax  and  the  zincs  added  quickly  in  smaU  pieces, 
stirring  the  mass  meantime  with  a  pipe-clay  stem.  It  is  then, 
on  the  fumes  of  the  zinc  passing  off,  immediately  poured  into 
an  ingot-mold  or  into  a  large  wooden  pail  filled  with  water; 
4  grains  of  this  alloy  melted  with  20  grains  of  pure  gold  will 
result  in  a  solder  fully  20  carats  fine. 

As  a  solder  for  crown-  and  bridge-work  constructed  of  22- 
carat  gold  plate,  Dr.  Litch's  formula  is  as  follows : 

Gold  coin  (ten  dollars),  258  grs  ; 
Spelter  (or  brazier's  solder),  24  grs.  ; 
Silver  coin,  24  grs. 

This  is  a  proportion  of  about  26  grains  of  pure  copper  and  232 
grains  of  pure  gold  to  the  remaining  48  grains  of  the  alloy,  and 
makes  a  gold  solder  a  little  over  18  carats  fine. 

Dr.  C.  M.  Richmond  originally  used  American  gold  coin  for 
forming  gold  crowns,  rolling  it  out  in  the  form  of  plate.  The 
scraps  he  formed  into  solder  by  melting  and  adding  one-fifth 
of  their  weight  of  fine  brass  wire  cut  in  small  pieces,  using 
plenty  of  borax. 

Dr.  Low's  formula  for  solder  in  bridge-work  is  : 

1  dwt.  coin  gold  ; 

2  grs.  copper ; 

4  grs.  silver. 

This  makes  a  solder  about  19  carats  fine. 


/ 


284  ARTIFICIAL  CROWN-  AND  BRIDGE- WORK. 

The  following  formula1  gives  a  20-carat  solder  which  is  specially 
lvommended  for  crown-  and  bridge-work: 

American  gold  coin  (21.6  carats  fine),  $10  piece,  258  grs.  ; 
Spelter  solder,  20.64  grs.        y    /  y» 

Sohhr  'F'dings. — R^oparcd  gold  solder  filings  are 
made  by  filing  with  a  clean,  flat  plate  file  a  thick  piece  of  solder 
held  in  a  vise.  The  filings  are  allowed  to  fall  in  a  box  or  on  a 
sheet  of  paper  placed  to  receive  them.  A  magnet  should  be 
passed  through  the  filings  to  remove  any  minute  particles  of 
steel.  To  five  parts  of  the  filings  so  made  is  added  and  well 
mixed  with  them  one  part  of  the  prepared  flux  or  finely  pul- 
verized  vitrified  borax.  Solder  prepared  in  this  way  is  useful 
for  strengthening  crowns,  and  also  in  fine  soldering  operations, 
as  the  particles  of  the  solder  take  the  heat  separately  and  fuse 
much  more  quickly  than  when  the  solder  is  cut  in  pieces.  The 
flow  of  the  solder  is  also  more  easily  limited. 

1  American  System  of  Dentistry,  vol.  iii,  p.  849. 


CHAPTER  II. 

PORCELAIN   TEETH. 

The  qualities  specially  requisite  in  the  body  of  porcelain  teeth 
for  use  in  crown-  and  bridge-work  are  density,  strength,  and  the 
ability  to  withstand  unaltered  in  form  or  shade  any  degree  of  heat 
to  which  they  may  necessarily  be  subjected.  In  these  respects 
the  porcelain  teeth  of  our  best  American  manufacture  seem  to 
excel,  besides  affording  the  most  artistic  imitation  of  the  natural 
teeth  in  form  and  shade.  They  are  also  distinguished  by  the 
practical  location  of  the  pins. 

In  some  crowning  operations,  where  to  imitate  the  conforma- 
tion of  a  natural  crown  considerable  alteration  of  the  labial 
surface  of  a  porcelain  front  is  required,  teeth  of  English  manu- 
facture may  be  used,  as  the  texture  of  the  porcelain  admits  of  a 
fine  polish  being  given  to  a  ground  surface. 

Teeth  are  sometimes  fractured  in  the  process  of  soldering, 
caused  by  the  contraction  of  the  backing  when  adapted  over 
the  edges  of  the  porcelain  in  a  curve  instead  of  at  a  right  or 
slightly  obtuse  angle,  or  by  melting  solder  on  some  point  of  the 
porcelain  which  is  unprotected  by  a  backing  of  metal.  The 
solder,  or  the  borax,  as  it  cools,  contracting  on  the  porcelain,  or 
a  very  thin  edge  of  the  metal  covering  it,  will  usually  cause  a 
fracture.  The  porcelain  tooth  has  yet  to  be  made  that  will,  as  a 
rule,  endure  such  extreme  treatment  without  breaking. 


285. 


rake  a  strip  of  thin  copper  ^  ",^?Xh£*  of*.  ^  at  th« 
in  the  mouth  or  its  form  on  the :  plaster  moae i.  n 

!d  are  next  en; as  shown  at  A   F.g  19, an    « «<«<£«£,,  ^  . 

nanner  seen  at  B.      lhis  lastenb   u uui  imoression  compound, 

ned  off  at  C,  forms  a  tube.     In  this  tube,  wit    a  ^P^J  either  in  the 
i  percha  or  moldine,  take  an  impression  o  nat ura   crow 

th  or  from  the  plaster  model  b-  fn^n.;; 
t  from  the  rest  of  the  mo^ 
iper  and  tube  with  ? 
ad  immerse  luh' 
•ik.  whi< 


parts 


lULLiiai    ^iu»"    «*»»—— 

'  the  tooth  or  by  separat- 

h  a  strip  of  paper.    Hold 

:'  'e  metal  moderately 

u  a  long  nar- 

■-ft¥Ot*l 


CHAPTER  III. 


MOLDS   AND   DIES. 


Metallic  models  of  fusible  metal  can  be  easily  and  quickly 
formed  for  use  in  crown- and  bridge-work.  The  melted  alloy 
'•;u i  be  poured  into  a  plaster,  moldine,  or  gutta-percha  impression 
taken  in  a  tube  or  impression-tray.,  W-hen^a  tuke-is-Trse^;  a  strip 
of  paper  should  be  wound  around>tf;  to  lengthen  the  die. 

The  following  fusible  alloys  of  tin  are  suitable  for  the  purpose: 


PROPORTIONS  OF 

METALS. 

MELTING    POINT   OF 
THE    ALLOY. 

Tin. 

Lead. 

Bismuth. 

Fahr. 

1 

2 

2 

236° 

5 

3 

3 

202° 

3 

5 

8 

197° 

Dr.  G.  W.  Melotte,  of  Ithaca,  N.  Y.,  to  whom  is  accorded  the 
credit  of  introducing  the  use  of  fusible  metal  and  the  compound 
called  "  moldine  "  into  crown-  and  bridge-work,  gives  the  propor- 
tions of  his  alloy  in  parts  as- — 

Tin,  6;  Lead,  3  ;  Bismuth,  8. 

Dr.  Melotte's  moldine,  a  preparation  compounded  of  potter's 
clay  and  glycerin  (to  which,  when  needed  to  soften  it,  more 
eerie  can  be  added),  is  very  useful  in  molding. 

A  counter-die  to  a  small  cas1  or  die  of  fusible  metal  is  made 
Iry  indenting  a  block  of  lead  with  a  punch,  and  then  driving  the 
casl  or  die  into  it.  Its  use  in  crown-work  is  described  on  pages 
96, 104,  and  10s,  and  l>y  Dr.  Melotte  on  page  233. 

The  following  method  of  forming  a  metallic  model  of  a  pre- 
pared  rool  or  crown  is  given  by  Dr.  W.  C.  Barrett,  of  Buffalo, 
X.  Y.,  \\h<>  accords  Dr.  II.  A.  Baker,  of  Boston,  the  credit  of 
being  the  originator  <>r  it: 

"Copper  is   rolled   down   quite   thin,  and  a  band  three-fourths 


J 


/ 


MOLDS  AND  DIES.  287 

of  an  inch  wide  wrapped  about  the  root  and  forced  up  under 
the  gum.  A  ligature  is  passed  around  both;  the  copper  band 
is  burnished  down  and  the  ligature  drawn  tight.  The  copper 
band  will  now  fit  just  as  we  want  the  gold  band  to  do.  Plaster 
of  Paris  is  then  inserted  in  this,  forced  up  against  the  end  of 
the  root,  and  permitted  to  set.  Take  it  off,  and  if  you  use 
Babbitt-metal,  a  piece  of  paper  wrapped  about  it  (the  copper 
band)  will  lengthen  it  out  sufficiently,  when  the  metal  may  be 
poured  into  it,  and  thus  a  perfect  model  of  the  end  of  the  root 
will  be  secured.  That  part  which  is  inserted  in  the  copper  tube 
is  the  exact  reproduction  of  the  root  of  the  tooth.  The  model 
will  perhaps  need  a  little  dressing  down  with  a  tile,  when  the 
gold  band  may  be  fitted  around  it  and  soldered,  thus  avoiding 
the  necessity  for  the  annoying  and  painful  trying-on  in  the 
mouth." 

Fusible  metal  can  be  used  instead  of  Babbitt-metal. 


Fig.  545. 


€* 


p^i  err  asun**^       -  '  ^ 

CHAPTER  IV. 

SOLDERING. 

Investments  for  soldering^  and  models 
on  which  the  soldering  is  to  be  done  for 
bridge-work,  are  made  in  calcined  mar- 
ble-dust and  plaster,  in  the  proportion 
of  equal  parts  for  models,  and  one  part 
of  plaster  to  two  of  marble-dust  for 
investing. (  SulphateW  potassium,  used 
in  place  of  common  salt,  but  in  smaller 
quantity,  will  cause  phe  mixture  to  set 
quickly  and  hard.        Y 

Soldering. — In  soldering  crown-  and 
bridge- work  or  sections  of  it  containing 
porcelain  fronts,  the  investment  should 
be  first  uniformly  and  thoroughly 
heated,  and  the  heat  maintained  during 
the  process  of  soldi  ring.  This  is  (.spe- 
cially necessary  in  the  final  soldering  of 
gold  crowns  with  porcelain  fronts,  as 
the  solder  is  thereby  flowed  into  the 
interstice-  between  the  porcelain  and 
the  caps  and  gives  continuity  of  struc- 
ture to  the  crown.  A  large  piece  of, 
charcoal,  concave  on  the  side  to  be  use( 
furnishes  a  good  soldering  support,  as 
it  retains  the  beat.  A  hand  gas  blow- 
pipe. (,],. iTated  by  a  foot  bellows,  and 
bo  constructed  thai  the  flame  is  under 
perfect  control,  is  the  must  suitable  (Fig. 
545). 

The  use  of  Borax. — In    soldering  in- 

jted    sections  of  a  crown   or   bridge 


•V: 


SOLDERING  289 

together,  borax  which  has  been  reduced  to  a  vitreous  state  by 
heat  and  then  finely  pulverized  is  the  preferred  form  for  its  use. 
Prepared  in  this  manner  it  should  be  sprinkled  on  the  part  pre- 
vious to  the  commencement  of  the  soldering,  and  a  little  added 
at  any  time  it  is  needed  during  the  continuance  of  the  process.1 
In  small,  tine  soldering  of  invested  or  uninvested  work,  the 
lump  borax  ground  with  water  on  a  slab  to  a  cream-like  con- 
sistence and  applied  witb  the  point  of  a  stick  or  brush  only 
where  it  is  desired  to  have  the  solder  flow,  is  the  most  suitable. 

1  Dr.  Purr's  "prepared  flux,"  a  finely  pulverized  vitrified  flux,  ean  be  used  in 
this  manner.  It  is  conveniently  kept  in  the  form  of  a  saturated  solution  in  a 
bottle,  from  which  the  operator  can  use  it  with  a  brush  or  stick  in  fine  soldering. 

It  is  also  prepared  in  combination  with  wax  cement.  In  the  melting  out  of  the 
wax  when  the  case  is  invested  and  heated  fur  soldering,  the  flux  is  carried  into 
the  interstices. 


19 


V 


CHAPTER    V. 

INSTRUMENTS  AND  APPLIANCES. 

The  dentist  who  intends  to  engage  extensively  in  crown-  and 
bridge-work,  and  who  desires  to  practice  it  conveniently  and  suc- 
cessfully, should  supply  himself  with  all  the  necessary  instru- 
ments, tools,  and  other  appliances.     These  consist  principally  of 

Fig.  54G. 


drills  of  various  styles,  among  them  the  Gates-Glidden  for  root- 
canals;  root-trimming  and  shaping  instruments;  corundum- 
wheels  and  points:  rubber  and  corundum  disks;  iuk  t  of  wfrdl 
numrfUJBlM ittMHnnitrn-1'iny  plwtr.  and  suitably  shaped  pliers;  tf 
iiiippl^ii'ir  clamp-  of  various  Forms  for  use  in  the  many  soldering 
processes  ;  some  moldine  and  fusible  alloy,  and  ;m  apparatus  for 
forming  gold  caps   for  use  in  constructing  crowns;   a  Lee  blow- 


1NSTR  UMEXTS  .  I  \I>  .  I  PPLL  I  XCES. 


291 


pipe  or  Knapp's  compound  blow-pipe,  or  both,  for  use  as  is  most 
suitable  or  convenient. 

The  bench  on  which  the  principal  parts  of  the  work  are  done 
should  be  specially  designed  and  reserved  tor  it.  It  should  be 
very,  convenient   to  the  dental  chair,  and  if  in  the  same  room 

Fig.  547. 


j5; 

should"  be  situated  a  little  behind  it,  out  of  view  of  the  patient. 

Everything  connected  with  this  bench  should  be  kept  in  order 

and  ready  for  immediate  use.     Such  a  bench,  made  of  black 

walnut,  with  a  top  that  can  be  closed  when  not  in  use,  making 

an  unobjectionable  piece  of   furniture,  is  represented  in  Figs. 

540  and  547./7  /  __ 

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